| Description | Date | Identifier | |
| Letter to John Marston Ltd. regarding prints, the ordering of motors and rheostats, and an arrangement with Lucas & A.C. Ltd. | 1st May 1939 | Box 137 \ 3 scan0077 | |
| Letter from the Experimental Department regarding the unsuitability of an air conditioning unit. | 1st May 1939 | Box 137 \ 3 scan0078 | |
| Correspondence regarding the unsuitability of an air conditioning unit and suggestions for modification. | 3rd May 1939 | Box 137 \ 3 scan0079 | |
| Letter to Lendrum & Hartman Ltd. regarding the testing of a borrowed Harrison defroster. | 5th May 1939 | Box 137 \ 3 scan0080 | |
| Letter of enquiry to Delco Remy & Hyatt Ltd. about American car heater and defroster units. | 6th May 1939 | Box 137 \ 3 scan0081 | |
| Despatch of a car heater spindle assembly to John Marstons Ltd. | 8th May 1939 | Box 137 \ 3 scan0082 | |
| Letter to John Marston Ltd. regarding the dispatch of parts for a car heater and a forthcoming 'Ripple' radiator design. | 8th May 1939 | Box 137 \ 3 scan0083 | |
| The progress of six car heaters. | 8th May 1939 | Box 137 \ 3 scan0084 | |
| Letter from John Marston Limited regarding the finish of a car heater and outstanding parts. | 9th May 1939 | Box 137 \ 3 scan0085 | |
| Chasing up the supply of fittings for an order of heaters with John Marston Ltd. | 9th May 1939 | Box 137 \ 3 scan0086 | |
| Letter from Delco-Remy & Hyatt Ltd. regarding American Car Heaters and Defrosters. | 11th May 1939 | Box 137 \ 3 scan0087 | |
| The despatch of a second heater spindle assembly to John Marstons Ltd. | 11th May 1939 | Box 137 \ 3 scan0088 | |
| Letter concerning the supply and assembly of car heaters and radiators. | 11th May 1939 | Box 137 \ 3 scan0089 | |
| Page 2 of a letter to John Marstons Ltd. regarding a meeting to discuss the manufacturing of a radiator. | 11th May 1939 | Box 137 \ 3 scan0090 | |
| Requesting a dashboard modification to accommodate a car heater on car 1.B.50. | 18th May 1939 | Box 137 \ 3 scan0091 | |
| Cover letter from Metalastik Ltd enclosing correspondence with John Marston Ltd regarding Heater Flexible Drives. | 20th May 1939 | Box 137 \ 3 scan0092 | |
| Copy of a letter to John Marston Limited regarding the supply and pricing of couplings for Heater Flexible Drives. | 20th May 1939 | Box 137 \ 3 scan0093 | |
| Letter from Metalastik Limited to John Marston Limited regarding the delivery of units. | 20th May 1939 | Box 137 \ 3 scan0094 | |
| Official order for flexible, wire imbedded hose for car heaters from The Dunlop Rubber Co. Ltd. | 23th May 1939 | Box 137 \ 3 scan0095 | |
| Letter from the Experimental Department to Dunlop Rubber Co. Ltd requesting further samples of imbedded wire type rubber hose. | 23th May 1939 | Box 137 \ 3 scan0096 | |
| Internal request to modify a Marston heater on car 1.B.50 to enable a flexible air duct to the rear compartment. | 23th May 1939 | Box 137 \ 3 scan0097 | |
| Letter from Metalastik Ltd forwarding a misdirected communication to Mr. Edwards of the Experimental Department. | 24th May 1939 | Box 137 \ 3 scan0098 | |
| Letter from Metalastik Limited enclosing a copy of another letter regarding Heater Flexible Drives. | 20th May 1939 | Box 137 \ 3 scan0099 | |
| Letter from Joseph Lucas Limited regarding a delay on Order No. 92440 for motors and switches. | 24th May 1939 | Box 137 \ 3 scan0100 | |
| Letter from Dunlop Rubber Co. Ltd. regarding the preparation and delivery of two special hose samples. | 25th May 1939 | Box 137 \ 3 scan0101 | |
| Comparison of a Smith Heater against the standard R.R. Marston heater, concluding the Smith heater is not superior. | 31th May 1939 | Box 137 \ 3 scan0102 | |
| Letter to Metalastik Ltd. confirming an agreement for Messrs. John Marstons to use a mould. | 31th May 1939 | Box 137 \ 3 scan0103 | |
| Car heater motor to be sent to Joseph Lucas Ltd. for modification. | 1st Jun 1939 | Box 137 \ 3 scan0104 | |
| Requesting Messrs. Lucas to produce two combined defroster duct and wiper spindle units from print PD.374. | 14th Jun 1939 | Box 137 \ 3 scan0105 | |
| Request to despatch a Harrison Power Defroster to Messrs. Lendrum & Hartman for the attention of Mr. Whitelock. | 14th Jun 1939 | Box 137 \ 3 scan0106 | |
| Request to Messrs. Lucas to manufacture two combined defroster duct and wiper spindle units from print PD.374. | 14th Jun 1939 | Box 137 \ 3 scan0107 | |
| Letter to Delco Remy & Hyatt Ltd. regarding a loaned catalogue and literature. | 14th Jun 1939 | Box 137 \ 3 scan0108 | |
| Letter regarding the testing and return of a loaned Harrison Power Defroster, noting its noisy operation. | 14th Jun 1939 | Box 137 \ 3 scan0109 | |
| Standardisation of heaters for Bentley V models. | 7th Jul 1939 | Box 137 \ 3 scan0110 | |
| From Rm. to Hn. confirming the correct policy has been adopted regarding heaters. | 11th Jul 1939 | Box 137 \ 3 scan0111 | |
| Requesting the return of a car heater to Messrs. John Marston for repair. | 12th Jul 1939 | Box 137 \ 3 scan0112 | |
| The standard fitment of heaters for Bentley 'A' Series and Wraith 'C' Series vehicles. | 14th Jul 1939 | Box 137 \ 3 scan0113 | |
| Requesting the production of two sets of defroster ducts. | 9th Aug 1939 | Box 137 \ 3 scan0114 | |
| Letter from John Marston Ltd. discussing the construction of a car heater matrix, comparing Mark III and Mark V types. | 10th Aug 1939 | Box 137 \ 3 scan0115 | |
| Test report comparing the heat dissipation efficiencies of Mark III and Mark V car heater matrices. | 4th Aug 1939 | Box 137 \ 3 scan0116 | |
| Letter to Clayton Dewandre Co. Ltd. requesting a combined heater and defroster unit for testing and a price quote for bulk orders. | 11th Aug 1939 | Box 137 \ 3 scan0117 | |
| Internal request to place an order for a heater and defroster unit from The Clayton Dewandre Co. Ltd. | 11th Aug 1939 | Box 137 \ 3 scan0118 | |
| Letter from Clayton Dewandre Company regarding the supply and installation of a car heater and demister unit. | 12th Aug 1939 | Box 137 \ 3 scan0119 | |
| Price quotation for bulk quantities of heater units. | 12th Aug 1939 | Box 137 \ 3 scan0120 | |
| Telex-style message confirming a meeting time for Thursday. | 15th Aug 1939 | Box 137 \ 3 scan0121 | |
| Telegram confirming an 11.30 AM meeting on Thursday for Edwards, sent by Blomeley Titanic. | 21th Aug 1931 | Box 137 \ 3 scan0122 | |
| Letter from Clayton Dewandre Co. Ltd. confirming the contents of telegrams exchanged regarding a meeting. | 15th Aug 1939 | Box 137 \ 3 scan0123 | |
| Fitting defroster ducts to model 33.G.VII. | 16th Aug 1939 | Box 137 \ 3 scan0124 | |
| Test results for a Mark III heater matrix and recommending its adoption over the Mark V. | 16th Aug 1939 | Box 137 \ 3 scan0125 | |
| The despatch of a car heater to Messrs. John Marston Ltd. for repair. | 21th Aug 1939 | Box 137 \ 3 scan0126 | |
| Request to make two right-angle copper pipe bends for a Clayton car heater. | 21th Aug 1939 | Box 137 \ 3 scan0127 | |
| Visit to John Marstons discussing corrosion in the Phantom III engine and potential remedies. | 25th Aug 1939 | Box 137 \ 3 scan0128 | |
| Status report on a corrosion inhibitor, car heaters, B.V. radiator modifications, Wraith 30 yoke costs, and a pressure-cooled radiator. | 25th Aug 1939 | Box 137 \ 3 scan0129 | |
| Brief typed memo regarding the construction of item SCD.1179 by Marstons. | 25th Aug 1939 | Box 137 \ 3 scan0130 | |
| Blanking plate for use on the Wraith III dashboard when a car heater is not fitted. | 25th Aug 1939 | Box 137 \ 3 scan0131 | |
| Blueprint for a blanking plate used when a heater is not fitted on a Wraith III. | 23th Aug 1939 | Box 137 \ 3 scan0132 | |
| Letter from Clayton Dewandre Company requesting the urgent return of a sample Car Heater & De-mister set. | 26th Sep 1939 | Box 137 \ 3 scan0133 | |
| Letter to Clayton Dewandre Co. Ltd. explaining a delay in testing a car heater due to the start of hostilities. | 28th Sep 1939 | Box 137 \ 3 scan0134 | |
| Letter from Clayton Dewandre Co. Ltd. concerning a Clayton Car Heater & De-Mister. | 30th Sep 1939 | Box 137 \ 3 scan0135 | |
| Letter to a supplier requesting a Rheostat switch for a 12-volt motor. | 31th Oct 1939 | Box 137 \ 3 scan0136 | |
| Letter from Clayton Dewandre Company Limited regarding the dispatch of a Rheostat Switch. | 3rd Nov 1939 | Box 137 \ 3 scan0137 | |
| Official order for a Rheostat Switch be sent to Clayton Dewandre Co. Ltd. | 7th Nov 1939 | Box 137 \ 3 scan0138 | |
| Supply and fitting of a defroster unit from Messrs. Lucas. | 15th Nov 1939 | Box 137 \ 3 scan0139 | |
| Modification and testing of strengthened 3rd speed dogs for the Senior Rationalised Gearbox. | 16th Nov 1939 | Box 137 \ 3 scan0140 | |
| List of new and replaced parts related to strengthened 3rd speed dogs for different gearbox configurations. | 16th Nov 1939 | Box 137 \ 3 scan0141 | |
| Querying whether two incorrectly supplied Rheostat Switches can be accepted following a supplier mix-up. | 1st Dec 1939 | Box 137 \ 3 scan0142 | |
| Requesting the despatch of a rheostat switch to Messrs. Clayton Dewandre Ltd. as it was sent in error. | 4th Dec 1939 | Box 137 \ 3 scan0143 | |
| Return of a located second switch to Messrs. Clayton Dewandre as it is not required. | 4th Dec 1939 | Box 137 \ 3 scan0144 | |
| Dispatch instruction to Messrs. Clayton-Dewandre Co. Ltd. for a surplus Rheostat Switch. | 5th Dec 1939 | Box 137 \ 3 scan0145 | |
| Return of an order form slip for defrosters from The Derby Factoring Co. | 12th Dec 1939 | Box 137 \ 3 scan0146 | |
| The procurement of 6 heater motors from Lucas Ltd. for experimental cars. | 18th Dec 1939 | Box 137 \ 3 scan0147 | |
| Request to manufacture a centrifugal car heater fan with specified blade dimensions. | 18th Jan 1940 | Box 137 \ 3 scan0148 | |
| Letter to Messrs. Clayton, Dewandre Ltd. regarding the testing of their car heaters, noting noise issues and requesting comparative performance figures. | 26th Jan 1940 | Box 137 \ 3 scan0149 | |
| Letter from S. Smith & Sons requesting a meeting to discuss the design of car heaters. | 26th Jan 1940 | Box 137 \ 3 scan0150 | |
| Letter from Clayton Dewandre Co. Ltd. concerning car heater tests and a proposed meeting. | 29th Jan 1940 | Box 137 \ 3 scan0151 | |
| Official order for six heater couplings from Leyland & Birmingham Rubbers Co. Ltd. | 31th Jan 1940 | Box 137 \ 3 scan0152 | |
| Letter to The Leyland & Birmingham Rubber Co. Ltd. regarding an urgent order for heater coupling pieces. | 31th Jan 1940 | Box 137 \ 3 scan0153 | |
| Letter confirming a telephone request for a five or six-point multiple switch for a motor car dashboard. | 1st Feb 1940 | Box 137 \ 3 scan0154 | |
| Letter from Clayton Dewandre Company Limited confirming travel arrangements. | 1st Feb 1940 | Box 137 \ 3 scan0155 | |
| Enquiry to Klaxons Ltd. for the supply of a silent electric motor for a special car heater installation. | 2nd Feb 1940 | Box 137 \ 3 scan0156 | |
| Visit from a representative of Clayton Dewandre Ltd. regarding car heater designs. | 2nd Feb 1940 | Box 137 \ 3 scan0157 | |
| Enquiries regarding Clayton Heaters, rheostats, and airflow measurement instruments. | 2nd Mar 1940 | Box 137 \ 3 scan0158 | |
| Note about the cancellation of a car heater order by S.S. Motors and the subsequent unavailability of another heater type. | 2nd Mar 1940 | Box 137 \ 3 scan0159 | |
| Letter to S.Smith & Sons Ltd. regarding the rescheduling of a discussion on heaters due to weather conditions. | 2nd Feb 1940 | Box 137 \ 3 scan0160 | |
| Request to order a five-way S.P. Rotary heater switch from Messrs. A. F. Bulgin & Co. Ltd. | 5th Feb 1940 | Box 137 \ 3 scan0161 | |
| Letter from Clayton Dewandre Co. Ltd. regarding the design and testing of experimental car heaters. | 5th Feb 1940 | Box 137 \ 3 scan0162 | |
| Letter from S. Smith & Sons acknowledging a letter and explaining a delay due to staff sickness. | 5th Feb 1940 | Box 137 \ 3 scan0163 | |
| Modifying a Rolls-Royce Marston car heater matrix and a request for Bentley steam valves and filler caps. | 6th Feb 1940 | Box 137 \ 3 scan0164 | |
| Letter from S. Smith & Sons regarding an appointment for car heaters. | 6th Feb 1940 | Box 137 \ 3 scan0165 | |
| Letter from The Leyland & Birmingham Rubber Co Ltd confirming the supply of rubber tubes for drawing No. D.B.2561. | 7th Feb 1940 | Box 137 \ 3 scan0166 | |
| Preliminary layout drawing for a Type 16T clutch. | 10th Feb 1940 | Box 137 \ 3 scan0167 | |
| Letter to S. Smith & Sons Ltd. arranging a visit to discuss car heaters. | 10th Feb 1940 | Box 137 \ 3 scan0168 | |
| Enquiry to Tok Switches Ltd. for particulars of a small rotary three-way switch. | 13th Feb 1940 | Box 137 \ 3 scan0169 | |
| Letter to Joseph Lukas Ltd. requesting particulars of a small rotary three-way switch. | 13th Feb 1940 | Box 137 \ 3 scan0170 | |
| Letter of inquiry to M.K. Electric Ltd. regarding a small rotary three-way switch for a motor car instrument board. | 13th Feb 1940 | Box 137 \ 3 scan0171 | |
| Letter requesting particulars for a small rotary three-way switch for an instrument board. | 13th Feb 1940 | Box 137 \ 3 scan0172 | |
| Requesting the dispatch of a heater motor and coupling to Clayton Dewandre Ltd. for testing. | 13th Feb 1940 | Box 137 \ 3 scan0173 | |
| Letter to British Thomson Houston Ltd. requesting particulars for a small rotary three-way switch for a motor car instrument board. | 13th Feb 1940 | Box 137 \ 3 scan0174 | |
| Inquiry to Messrs. Crabtree & Co. Ltd. for details on a small rotary three-way switch for a motor car. | 13th Feb 1940 | Box 137 \ 3 scan0175 | |
| Letter to Messrs. Ferranti Ltd. requesting details for a small rotary three-way switch for a motor car. | 13th Feb 1940 | Box 137 \ 3 scan0176 | |
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