| Description | Date | Identifier | |
| Letter discussing the issue of excessive headlamp and wing movement on certain car models and potential causes. | 9th Aug 1934 | Box 27a \ 1 Scan132 | |
| Letter to 'Rm' discussing the negative sales impact on Hispano-Suiza and potential effects on their own sales. | 31th Aug 1934 | Box 27a \ 1 Scan133 | |
| The delayed fitting of a headlamp cross-member to car B-I30-AH due to an accident in Belgium. | 31th Aug 1934 | Box 27a \ 1 Scan134 | |
| Customer feedback on competitor cars (Packard, Mercedes) and intelligence on Hispano's plans for a 24-hour race car. | 25th Oct 1934 | Box 27a \ 1 Scan135 | |
| Letter discussing premature bearing failure in Bentley cars and the proposed customer service response. | 24th Oct 1934 | Box 27a \ 1 Scan136 | |
| Bentley big end bearing failures, attributing them to atmospheric temperature and proposing necessary modifications. | 26th Oct 1934 | Box 27a \ 1 Scan137 | |
| Internal communication regarding a forthcoming bearing modification and advising against strenuous vehicle use in hot weather. | 26th Oct 1934 | Box 27a \ 1 Scan138 | |
| Letter discussing an article from the French paper 'l'Auto' that generated many enquiries about the Bentley. | 26th Oct 1934 | Box 27a \ 1 Scan139 | |
| French press article reviewing the performance and qualities of a silent Bentley grand sport car. | 29th Oct 1934 | Box 27a \ 1 Scan140 | |
| Bentley bearings. | 29th Oct 1934 | Box 27a \ 1 Scan141 | |
| Private letter discussing a policy for inspecting and dealing with defective Bentley big end bearings. | 29th Oct 1934 | Box 27a \ 1 Scan142 | |
| Cracked big end bearings on a demonstrator car, listing potential customers at risk, and proposing proactive maintenance to uphold Bentley's reputation. | 29th Oct 1934 | Box 27a \ 1 Scan143 | |
| Supply and approval of lead bronze Bentley bearings. | 30th Oct 1934 | Box 27a \ 1 Scan144 | |
| Private letter discussing recurring failures of Bentley big end bearings and proposing a discretionary inspection policy. | 29th Oct 1934 | Box 27a \ 1 Scan145 | |
| Potential vehicle issue, listing concerned customers, and emphasizing the importance of brand reputation and durability. | 29th Oct 1934 | Box 27a \ 1 Scan146 | |
| Suggestions for testing lead bronze Bentley bearings. | 1st Nov 1934 | Box 27a \ 1 Scan147 | |
| Stringent oil regulations required if lead bronze bearings are adopted for the chassis. | 12th Nov 1934 | Box 27a \ 1 Scan148 | |
| Scheduling, condition, and recent use of car B-49-BL for continental trials. | 14th Nov 1934 | Box 27a \ 1 Scan149 | |
| Car's performance during Continental Trials, arranging for an inspection in Paris and a potential follow-up in Derby. | 15th Nov 1934 | Box 27a \ 1 Scan150 | |
| Customer complaint about the performance of a 20/25 HP car following a carburetter change. | 15th Nov 1934 | Box 27a \ 1 Scan151 | |
| Complaint about the performance of a 20/25 HP car's new carburetter and outlining solutions. | 15th Nov 1934 | Box 27a \ 1 Scan152 | |
| Clarifying the condition and status of car B.49.BL after continental trials, including bodywork issues and travel restrictions. | 19th Nov 1934 | Box 27a \ 1 Scan153 | |
| Customer complaints about the poor acceleration performance of the 20/25 HP model. | 19th Nov 1934 | Box 27a \ 1 Scan154 | |
| Performance issues and testing results for several vehicles, including a Bentley and a Dubonnet car. | 19th Nov 1934 | Box 27a \ 1 Scan155 | |
| The Continental Trials of vehicle B-49-BL. | 20th Nov 1934 | Box 27a \ 1 Scan156 | |
| Bentley's high-speed performance, future racing plans, and the feasibility of increasing the compression ratio on a 20/25 model. | 22th Nov 1934 | Box 27a \ 1 Scan157 | |
| Higher compression ratio on the 20/25 model for the Continent. | 24th Nov 1934 | Box 27a \ 1 Scan158 | |
| Why top speed acceleration features of the 20/25 HP Chassis were not stressed to the Sales department. | 24th Nov 1934 | Box 27a \ 1 Scan159 | |
| Higher compression modifications for the 20/25 model due to performance issues. | 26th Nov 1934 | Box 27a \ 1 Scan160 | |
| Vehicle performance, a high-speed encounter, and modifications for Bentley and 20/25 HP models. | 27th Feb 1934 | Box 27a \ 1 Scan161 | |
| Road test comparisons between an old 20/25 HP chassis and a newer model, chassis 21 G IV. | 27th Feb 1934 | Box 27a \ 1 Scan162 | |
| Follow-up memo regarding information on Hancock's visit to Paris, in connection with a 20/25 Chassis. | 29th Nov 1934 | Box 27a \ 1 Scan163 | |
| Forwarding a report from Hancock regarding the performance of a 20/25 HP Chassis, potentially affected by fuel used in Paris. | 30th Nov 1934 | Box 27a \ 1 Scan164 | |
| Bentley trial concerning bumper bar and cross member fittings. | 30th Nov 1934 | Box 27a \ 1 Scan165 | |
| An investigation into a carburetter issue. | 30th Nov 1934 | Box 27a \ 1 Scan166 | |
| Choice between bumper bars and cross members for two chassis, and a competitor's Renault vehicle. | 30th Nov 1934 | Box 27a \ 1 Scan167 | |
| Vehicle performance testing, carburetor adjustments, and comparison with other cars. | 30th Nov 1934 | Box 27a \ 1 Scan168 | |
| From Levallois to Derby regarding customer M. Poberejsky's complaints and a request for a high compression cylinder head for chassis GAE 2. | 1st Dec 1934 | Box 27a \ 1 Scan169 | |
| Instruction to machine .060' from a 25 HP cylinder head and ensure standard valves are ground in. | 1st Dec 1934 | Box 27a \ 1 Scan170 | |
| Letter regarding a 20/25 HP cylinder head and troubleshooting performance issues in France. | 3rd Dec 1934 | Box 27a \ 1 Scan171 | |
| Sending a special 20/25 HP cylinder head to Paris for performance tests on a 10,000 miles car. | 3rd Dec 1934 | Box 27a \ 1 Scan172 | |
| Higher compression cylinder head, top speed issues, and carburetter settings for chassis GAE-2. | 3rd Dec 1934 | Box 27a \ 1 Scan173 | |
| Letter discussing bumper bars for a Bentley chassis and a negative comparison of Renault cars. | 4th Dec 1934 | Box 27a \ 1 Scan174 | |
| Cylinder head compression ratios for the 20/25 model using different gaskets. | 5th Dec 1934 | Box 27a \ 1 Scan175 | |
| Performance issues of the 25 HP car in Paris and suggesting the 'Wraith' as the solution. | 5th Dec 1934 | Box 27a \ 1 Scan176 | |
| Requesting a reply regarding higher compression for the 20/25 model. | 5th Dec 1934 | Box 27a \ 1 Scan177 | |
| Notification about a delay in dispatching a 20/25 Higher Compression Cylinder Head due to a sparking plug issue. | 7th Dec 1934 | Box 27a \ 1 Scan178 | |
| Telegram from Poberejsky Leator chasing the overdue delivery of a cylinder head for Robotham. | 7th Dec 1934 | Box 27a \ 1 Scan179 | |
| Letter concerning the despatch of a high compression cylinder head and comparative tests for chassis GAE 2 and GAE 3. | 7th Dec 1934 | Box 27a \ 1 Scan180 | |
| Increasing the compression ratio for the 20/25 engine model. | 8th Dec 1934 | Box 27a \ 1 Scan181 | |
| New ignition advance characteristics required with a high compression head. | 8th Dec 1934 | Box 27a \ 1 Scan182 | |
| Testing a 20/25 cylinder head and requiring a different ignition tower for it. | 11th Dec 1934 | Box 27a \ 1 Scan183 | |
| 20/25 HP chassis performance, a customer complaint about a new carburetter, and options for a low geared axle. | 14th Nov 1934 | Box 27a \ 1 Scan184 | |
| The poor acceleration of the 20/25 HP chassis compared to its predecessor and competitors. | 7th Nov 1934 | Box 27a \ 1 Scan185 | |
| Extract from a Paris showroom report detailing customer feedback on car performance. | 7th Nov 1934 | Box 27a \ 1 Scan186 | |
| List of individuals who took part in trials for the 25 HP Pendant Saloon, with notes on who rejected the vehicle. | 3rd Nov 1934 | Box 27a \ 1 Scan187 | |
| Performance comparison between a new 20/25 HP chassis (GAE-5) and an older model with an old type carburetter. | 14th Nov 1934 | Box 27a \ 1 Scan188 | |
| Performance of the 20/25 HP Chassis, the merits of a new carburetter, and a performance comparison with a Buick. | 15th Nov 1934 | Box 27a \ 1 Scan189 | |
| Customer reactions to performance improvements, comparing new cars to well run-in chassis. | 15th Nov 1934 | Box 27a \ 1 Scan190 | |
| Performance improvements for the 20/25 model, focusing on the ignition system and component changes. | 12th Dec 1934 | Box 27a \ 1 Scan191 | |
| Parts being despatched for testing on Chassis 21.G.IVi in France. | 12th Dec 1934 | Box 27a \ 1 Scan192 | |
| Brief typed letter from Levallois confirming receipt of a previous communication. | 15th Dec 1934 | Box 27a \ 1 Scan193 | |
| Road test in Paris comparing a modified car's acceleration against a standard model after fitting a high compression head. | 27th Dec 1934 | Box 27a \ 1 Scan194 | |
| The disappointing performance results of a car fitted with a high compression head. | 27th Dec 1934 | Box 27a \ 1 Scan195 | |
| Letter discussing test results and impressions of a 20/25 HP car with a high compression cylinder head. | 29th Dec 1934 | Box 27a \ 1 Scan196 | |
| High compression cylinder head and a tappet silencing scheme from Hispano. | 31th Dec 1934 | Box 27a \ 1 Scan197 | |
| Letter discussing the feasibility of fitting a high compression cylinder head to a 20/25 demonstration car. | 31th Dec 1934 | Box 27a \ 1 Scan198 | |
| Power output performance graph for a 20/25 HP engine with different cylinder head specifications. | 17th Feb 1934 | Box 27a \ 1 Scan199 | |
| Page stamped by the Derby Print Room. | 2nd Jan 1935 | Box 27a \ 1 Scan200 | |
| Graph comparing ignition advance curves for a 20/25 engine with different governor setups. | 17th Feb 1934 | Box 27a \ 1 Scan201 | |
| Fitting a high compression cylinder head to a Paris demonstration car. | 1st Jan 1935 | Box 27a \ 1 Scan202 | |
| The manufacture and fitting of lead bronze bearings, and the necessary modifications required. | 1st Jan 1935 | Box 27a \ 1 Scan203 | |
| Approval for fitting a non-standard high compression cylinder head to a Paris Trials Car. | 2nd Jan 1935 | Box 27a \ 1 Scan204 | |
| Telegram concerning the inability to acquire a high compression cylinder head. | 5th Jan 1934 | Box 27a \ 1 Scan205 | |
| Hancock's report on a High Compression Cylinder Head and requesting that the tests be repeated due to unsatisfactory results. | 3rd Jan 1935 | Box 27a \ 1 Scan206 | |
| Letter discussing customer feedback on a high compression cylinder head and comparing it to other engines. | 3rd Jan 1935 | Box 27a \ 1 Scan207 | |
| Acknowledging information and methods regarding lead bronze bearings. | 7th Jan 1935 | Box 27a \ 1 Scan208 | |
| Telegram requesting the urgent shipment of a bumper bar and cross member for a Bentley. | 11th Jan 1935 | Box 27a \ 1 Scan209 | |
| Letter concerning parts for M. Michelin's Bentley regarding a front wing movement issue. | 12th Jan 1935 | Box 27a \ 1 Scan210 | |
| Night letter telegram confirming the dispatch of parts for a Michelin bumper bar. | 14th Jan 1935 | Box 27a \ 1 Scan211 | |
| The fitting of a bumper bar to M. Michelin's Bentley, referencing parts and drawings. | 14th Jan 1935 | Box 27a \ 1 Scan212 | |
| Questioning why a telephone call charge was debited to Experimental expenses. | 14th Jan 1935 | Box 27a \ 1 Scan213 | |
| Requesting particulars for the Solex carburetter on the Hispano. | 15th Jan 1935 | Box 27a \ 1 Scan214 | |
| Letter discussing a repair for lamp and wing movement on a Bentley, and rescheduling the work on Mr. Hauvette's car. | 16th Jan 1935 | Box 27a \ 1 Scan215 | |
| Report outlining faults on chassis B 179 AE and requesting advice on dynamo output and pivot pin bush issues. | 16th Jan 1935 | Box 27a \ 1 Scan216 | |
| Letter detailing a meeting with the Managing Director of the Solex Company regarding carburetor blueprints. | 17th Jan 1935 | Box 27a \ 1 Scan217 | |
| Altered voltage control regulator and seized pivot pin bushes requiring more oil. | 19th Jan 1935 | Box 27a \ 1 Scan218 | |
| Solex blue prints and requesting to obtain a carburetter for testing. | 21th Jan 1935 | Box 27a \ 1 Scan219 | |
| Letter discussing a body boom or drumming noise on Chassis III.SK - BLACKMER. | 22th Jan 1935 | Box 27a \ 1 Scan220 | |
| Correspondence regarding the supply and fitting of a Solex carburettor. | 23th Jan 1935 | Box 27a \ 1 Scan221 | |
| Technical note discussing pivot pin seizure and loose engine mounting bolts on chassis B-179-AE. | 24th Jan 1935 | Box 27a \ 1 Scan222 | |
| Technical letter providing a detailed troubleshooting guide for resolving booming and vibration issues on a car. | 25th Jan 1935 | Box 27a \ 1 Scan223 | |
| Report discussing body construction methods to prevent panel diaphragming and boom. | 25th Jan 1935 | Box 27a \ 1 Scan224 | |
| Letter discussing the design and efficiency of a special type of scraper ring, also known as a scavenger ring. | 26th Jan 1935 | Box 27a \ 1 Scan225 | |
| Letter detailing the fitting of new connecting rods and bearings to a Bentley chassis, including measurements, wear, and road test observations. | 29th Jan 1935 | Box 27a \ 1 Scan226 | |
| Intelligence on a new 12-cylinder Lincoln car, with a handwritten annotation about the new Small Packard. | 30th Jan 1935 | Box 27a \ 1 Scan227 | |
| Oil supply failures to the pivot pins on two Bentley chassis, discussing fractured pipe lines and rust issues. | 30th Jan 1935 | Box 27a \ 1 Scan228 | |
| Letter discussing scraper ring efficiency, piston collapse, and oil consumption in Bentley cars with Aerolite pistons. | 31th Jan 1935 | Box 27a \ 1 Scan229 | |
| Letter discussing headlamp wiring faults, horn modifications, and demonstrator car upgrades. | 1st Feb 1935 | Box 27a \ 1 Scan230 | |
| Wiring diagram for a foot-operated Bosch headlight switch, Bentley type. | 2nd Feb 1935 | Box 27a \ 1 Scan231 | |
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