Until the advent of the DVLA in 1977 vehicle licencing records were maintained locally as hand written ledgers by your local town Hall. I recently did some research into the early history of my Triumph and contacted Hertfordshire Council for a copy of the relevant page which duly arrived within a fortnight. As was typical in the trade, the garage that sold mine - Herts Motors, St Albans - had taken out a block booking of 10 registration numbers at the start of the month - TUR241J to TUR250J, called up as cars were sold. One of those was subsequently unused (if anyone is looking for a Triumph related number for an imported 1970 car I guess it would still be available) These records are rather fickle depending on where you are, with Hertfordshire only recording the registration number, 'to whom allocated' and date first registered, whereas (For instance) the Bournemouth records which are now held at Dorchester, detail the registration number, agent, make and model, name of customer and date first registered. A document from that source therefore also provides a fascinating insight into what other vehicles were being sold and to what sort of customers. In March 1963 for instance among the mix of private and commercial customers, W.H.Smiths bought a single Ford Cortina from Hendys Bros, and the S.E.B. Yeovil bought a Morris 6cwt van direct from Morris, but of the 35 vehicles listed in that two week period, just 3 were Triumphs - all of them Heralds. Going back to the Hertfordshire listing, Herts Motors were at 21-23 London Road, St Albans. Centrally placed as were so many dealers back then and now inevitably redeveloped as flats. If anyone has any information or an image of this dealership I'd be interested to hear. In the meantime I've made a low resolution pdf file up of the 'Triumph Sales and Service Directory' booklet for March 1970 that came in the glovebox of my car when I bought it in 1989 so you can play the 'what are the dealerships now' game... (Attached)
Triumph SSD March 1970.pdf