| Description | Date | Identifier | |
| Changes to springs, side levers, sub-frames, and gearbox production for 20 HP and 40/50 HP models. | 10th Jun 1925 | Box 57 \ 1 Scan149 | |
| The schedule for introducing new parts like side levers and gearcases after a 10,000-mile trial. | 11th Jun 1925 | Box 57 \ 1 Scan150 | |
| Modifications to an 'India' car, detailing tests on the brakes, stiffer springs, and gearbox. | 11th Jun 1925 | Box 57 \ 1 Scan151 | |
| Tests involving reducing splines on gears for 4-speed 20 HP gearboxes. | 1st May 1925 | Box 57 \ 1 Scan152 | |
| Servo efficiency and torque multiplication. | 11th Jun 1925 | Box 57 \ 1 Scan153 | |
| Calculation sheet for the output and torque multiplication of the 'India' Servo system. | 11th Jun 1925 | Box 57 \ 1 Scan154 | |
| Schematic of modified brake levers with a corresponding chart analyzing braking distribution and efficiency versus servo torque. | 15th Jun 1925 | Box 57 \ 1 Scan155 | |
| Testing of plain versus louvred bonnets on various car models to address overheating, and related scheduling. | 15th Jun 1925 | Box 57 \ 1 Scan156 | |
| Chassis improvements, focusing on the benefits of stronger front springs and changes to front wheel brakes. | 20th Jun 1925 | Box 57 \ 1 Scan157 | |
| Gearbox pinion and spline issues, detailing a successful solution involving a torsionally free double pinion. | 20th Jun 1925 | Box 57 \ 1 Scan158 | |
| Technical note regarding clearances for the gate and interlock in a sliding gear mechanism. | 22th Jun 1925 | Box 57 \ 1 Scan159 | |
| Body and delivery schedule for a 20 HP car for Mr. Royce's personal use. | 22th Jun 1925 | Box 57 \ 1 Scan160 | |
| The 'India' car fitted with 4-wheel brakes, detailing spring specifications and sales approval. | 22th Jun 1925 | Box 57 \ 1 Scan161 | |
| Need to test a car with a closed body rather than an open one, questioning the difference in springs. | 23th Jun 1925 | Box 57 \ 1 Scan162 | |
| Secret memo regarding arrangements to bring the Experimental 'India' open car to London. | 23th Jun 1925 | Box 57 \ 1 Scan163 | |
| Secret memo regarding a 20 HP car for Mr. Royce, discussing body fitting and chassis components. | 6th Jun 1925 | Box 57 \ 1 Scan164 | |
| Secret memo from Hs. to BJ. regarding modifications to a Barker limousine to test springs for 'India'. | 24th Jun 1925 | Box 57 \ 1 Scan165 | |
| Secret report from India on issues with chassis 9.G.111 after 5726 miles, focusing on gearbox and bearing problems. | 25th Jun 1925 | Box 57 \ 1 Scan166 | |
| Secret memo from 'R.' to 'HS.' requesting an India open car for testing purposes. | 29th Jun 1925 | Box 57 \ 1 Scan167 | |
| Replying to points raised about materials, an oil drain hole, and bearings. | 1st Jul 1925 | Box 57 \ 1 Scan168 | |
| Secret memo about sending car 8-G-111 for use and car 9-G-111 to France for a 10,000-mile test. | 18th Jul 1925 | Box 57 \ 1 Scan169 | |
| Modifications to a 20 HP car fitted with 4-wheel brakes. | 12th Jun 1925 | Box 57 \ 1 Scan170 | |
| The condition and planned testing of car 9-G-111 before its dispatch to France. | 23th Jul 1925 | Box 57 \ 1 Scan171 | |
| Modifications and tests for 4-wheel brake systems on 20 HP cars. | 23th Jul 1925 | Box 57 \ 1 Scan172 | |
| Brake squeak issues and damper efficiency on various car models. | 23th Jul 1925 | Box 57 \ 1 Scan173 | |
| Outlining the plan for a 10,000-mile endurance run of a 20 HP car in France. | 23th Jul 1925 | Box 57 \ 1 Scan174 | |
| Mr. Royce's use of a 20 HP car for his holiday and its unsuitability as a Trials car. | 1st Jul 1925 | Box 57 \ 1 Scan175 | |
| Vehicle unsteadiness caused by semi-balloon tyres and the improvement from increasing front shock absorber friction. | 24th Jul 1925 | Box 57 \ 1 Scan176 | |
| Secret memo detailing a road test of a modified India chassis, focusing on braking, comfort, and gearbox performance. | 24th Jul 1925 | Box 57 \ 1 Scan177 | |
| Requesting arrangements for a test drive of a 20 HP car to Frinton. | 27th Jul 1925 | Box 57 \ 1 Scan178 | |
| The despatch and known faults of the India Type Chassis. | 10th Aug 1925 | Box 57 \ 1 Scan179 | |
| Request for a 20 HP car for use in France, offering an old type car (6-G-11) for this purpose and outlining its preparation for sale. | 17th Aug 1925 | Box 57 \ 1 Scan180 | |
| Secret memo regarding a 10,000-mile test of the India Chassis in France. | 8th Aug 1925 | Box 57 \ 1 Scan181 | |
| Preparation and delivery of a car to Conduit Street with a rear windscreen and works-grey paint. | 8th Aug 1925 | Box 57 \ 1 Scan182 | |
| Issues with car 9-G-111 after a 2,500-mile road test, covering engine guards, steering, and propeller shaft fouling. | 8th Aug 1925 | Box 57 \ 1 Scan183 | |
| Chassis 9-G-111 after 2,500 miles, detailing engine condition. | 14th Aug 1925 | Box 57 \ 1 Scan184 | |
| The condition and function of various vehicle components. | 14th Aug 1925 | Box 57 \ 1 Scan185 | |
| The condition of various car components. | 14th Aug 1925 | Box 57 \ 1 Scan186 | |
| The performance of various vehicle components including steering, axle, suspension, clutch, and gearbox. | 1st Aug 1925 | Box 57 \ 1 Scan187 | |
| Issues with servo gears, starter motor, brakes, and other vehicle components. | 14th Aug 1925 | Box 57 \ 1 Scan188 | |
| The condition of various vehicle components. | 12th Jun 1925 | Box 57 \ 1 Scan189 | |
| Vehicle examination, test results and required repairs. | 14th Aug 1925 | Box 57 \ 1 Scan190 | |
| The lack of designs for a damped pendulum lever and a cutout for the 20 HP model. | 27th Aug 1925 | Box 57 \ 1 Scan191 | |
| Proposed carburetter modifications on the 20 HP car to increase power and improve performance against competitors. | 1st Sep 1925 | Box 57 \ 1 Scan192 | |
| Various mechanical issues found during a 10,000-mile test of the 9-G-111 car in France. | 10th Sep 1925 | Box 57 \ 1 Scan193 | |
| Analysis of a steering support failure on car 9-G-111 and proposed alterations based on the Phantom model. | 10th Aug 1925 | Box 57 \ 1 Scan194 | |
| Standardisation of chassis parts for the 20 HP model fitted with 4-wheel brakes and a 4-speed gearbox. | 10th Aug 1925 | Box 57 \ 1 Scan195 | |
| Low speed steering wobble on the 20-HP chassis and whether to halt deliveries pending modification. | 17th Sep 1925 | Box 57 \ 1 Scan196 | |
| Cost difference for standardising a 20 HP chassis with 4-wheel brakes and a 4-speed gearbox. | 21th Sep 1925 | Box 57 \ 1 Scan197 | |
| Halting the delivery of the 20 HP 'India' chassis pending design alterations following a 10,000 miles test. | 22th Sep 1925 | Box 57 \ 1 Scan198 | |
| Outlining urgent modifications for the 20 HP model's steering system. | 12th Jun 1925 | Box 57 \ 1 Scan199 | |
| Concerning delivery issues with the 'India' chassis, including servo and steering problems. | 1st Sep 1925 | Box 57 \ 1 Scan200 | |
| Potential pre-delivery alterations to production cars, specifically the 'INDIA' model. | 25th Sep 1925 | Box 57 \ 1 Scan201 | |
| Secret internal memorandum discussing modifications and issues with the carburetter, dynamo, steering, and front axle. | 22th Aug 1925 | Box 57 \ 1 Scan202 | |
| Various technical issues and observations on a vehicle's components. | 30th Sep 1925 | Box 57 \ 1 Scan203 | |
| Correcting a car's poor running by adjusting valve clearances and strengthening the jets. | 30th Sep 1925 | Box 57 \ 1 Scan204 | |
| A delivery delay for three 20 HP cars pending a decision on alterations. | 30th Sep 1925 | Box 57 \ 1 Scan205 | |
| Serious front axle twisting fault on the 'India' project. | 1st Oct 1925 | Box 57 \ 1 Scan206 | |
| Faults and delivery of the 'India' chassis, including servo issues and a new front axle design. | 5th Oct 1925 | Box 57 \ 1 Scan207 | |
| Running experience of Phantom and India cars, focusing on chassis weight and hydraulic shock damper design. | 27th Oct 1925 | Box 57 \ 1 Scan208 | |
| Test report on Chassis No. 9-G-3, detailing steering performance and other observed issues. | 2nd Nov 1925 | Box 57 \ 1 Scan209 | |
| Request for parts for an Experimental Cabriolet 10-G-3. | 7th Nov 1925 | Box 57 \ 1 Scan210 | |
| Log of engineering modifications and experiments, including for the 20HP chassis, from 1925. | 19th Nov 1925 | Box 57 \ 1 Scan211 | |
| Responding to criticisms of the 20 HP chassis, comparing its brakes, oil filter, and lubrication to a Bentley. | 23th Nov 1925 | Box 57 \ 1 Scan212 | |
| List of modifications for the 20 HP model following a 10,000 miles test. | 23th Nov 1925 | Box 57 \ 1 Scan213 | |
| Issues and improvements for carburation, dynamo, and ignition systems. | 23th Nov 1925 | Box 57 \ 1 Scan214 | |
| List of experiments and modifications for the 20-HP Chassis. | 4th Dec 1925 | Box 57 \ 1 Scan215 | |
| Letter to coachbuilders Barkers about sending a 20 HP car. | 21th Dec 1925 | Box 57 \ 1 Scan216 | |
| Request for experimental reports on various faults found on the 20 HP chassis. | 12th Jan 1926 | Box 57 \ 1 Scan217 | |
| Proposed standard tests for oiling, subframe, and power consumption on 20 HP cars. | 15th Jan 1926 | Box 57 \ 1 Scan218 | |
| New features on a 20 HP car being sent for a 10,000-mile test. | 15th Jan 1926 | Box 57 \ 1 Scan219 | |
| Modifications to the 20 HP model's connecting rods for a 10,000 mile run. | 19th Jan 1926 | Box 57 \ 1 Scan220 | |
| Outlining important items to be tested on the next 20 HP chassis for its 10,000-mile trial. | 29th Jan 1926 | Box 57 \ 1 Scan221 | |
| 20 HP chassis, discussing steering, pedal, and dashboard modifications. | 2nd Feb 1926 | Box 57 \ 1 Scan222 | |
| Telegram requesting modifications to a vehicle, specifically concerning steering, horsepower, and induction. | 16th May 1920 | Box 57 \ 1 Scan223 | |
| Logistics and car allocation for a 10,000-mile test of a 20 HP car in France. | 19th Feb 1926 | Box 57 \ 1 Scan224 | |
| Customer feedback on a 20 HP car's front-wheel-brake, slipper-drive, and carburettor. | 23th Feb 1926 | Box 57 \ 1 Scan225 | |
| Road test report and comparison between a 20 HP model and a Phantom, including feedback from W.O. Bentley. | 21th Feb 1926 | Box 57 \ 1 Scan226 | |
| Typed review and critique of a car, suggesting improvements to speed, braking, and bodywork aesthetics. | 21th Feb 1926 | Box 57 \ 1 Scan227 | |
| The conclusion of a memo proposing a test drive to assess a car's steering, brakes and roughness. | 1st Mar 1926 | Box 57 \ 1 Scan228 | |
| Expecting a list of customer complaints for Phantom and 20 HP models. | 1st Mar 1926 | Box 57 \ 1 Scan229 | |
| Visit to Le Canadel, the progress of an EAC.Vlll chassis, and a list of modifications for a 20 HP car. | 3rd Mar 1926 | Box 57 \ 1 Scan230 | |
| Continued memorandum regarding the fitting of hydraulic shock absorbers and car alterations. | 3rd Mar 1926 | Box 57 \ 1 Scan231 | |
| Data sheet for a 20 HP engine. | 5th Mar 1926 | Box 57 \ 1 Scan232 | |
| List detailing the specifications for a series of experimental cars, designated EAC.1 to EAC.7. | 5th Mar 1926 | Box 57 \ 1 Scan233 | |
| List describing specifications for a New Phantom and various 20 HP models. | 17th Mar 1926 | Box 57 \ 1 Scan234 | |
| 10,000-mile test of a 20 HP chassis, detailing new parts fitted and modifications made. | 17th Mar 1926 | Box 57 \ 1 Scan235 | |
| List of technical observations and modifications on various car components. | 17th Mar 1926 | Box 57 \ 1 Scan236 | |
| Continuation of a report listing car components with feedback on steering and weight. | 4th Apr 1926 | Box 57 \ 1 Scan237 | |
| Preparation of a 20 HP chassis for a 10,000-mile sales test. | 4th Apr 1926 | Box 57 \ 1 Scan238 | |
| New parts required to upgrade car 8-G-111 to a more modern 20 HP specification. | 21th Apr 1926 | Box 57 \ 1 Scan239 | |
| Proposal to update the 20 HP car, listing twelve new modern features to be fitted. | 30th Apr 1926 | Box 57 \ 1 Scan240 | |
| Performance impact of increasing compression on a 20 HP engine. | 1st May 1926 | Box 57 \ 1 Scan241 | |
| Proposing to hand over the completed experimental car 8-G-111 to the Repair Department for sale preparation. | 13th May 1926 | Box 57 \ 1 Scan242 | |
| Confirming a telegram and discussing faults and modifications for a servo drive and front braking system following a report from India. | 15th May 1926 | Box 57 \ 1 Scan243 | |
| Modifications to gear, worm, and spline designs, including a solution for damping squeaks. | 15th May 1926 | Box 57 \ 1 Scan244 | |
| Friction dampers, spring camber, and front wheel brakes. | 15th May 1926 | Box 57 \ 1 Scan245 | |
| Potential improvements to braking, servo, and suspension components. | 17th May 1926 | Box 57 \ 1 Scan246 | |
| Cost estimates and details for the sale of experimental car 8.G.111. | 17th May 1926 | Box 57 \ 1 Scan247 | |
| Modifications and requests for various car components and models. | 26th May 1926 | Box 57 \ 1 Scan248 | |
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