Hey Steve,
The London Roadster was assembled in Dearborn, Mich. on Michigan Ave, just west of Southfield. After I bought my Allison in ’82 , I visited London Roadster’s shop which at that time was thriving. As with so many it is now defunct. Regarding getting info , you might try the Dearborn City Hall , Dearborn , Mi. & ask for any info that they might have on the company. There are many devotees in the Detroit area & many car shows as well. My guess is that most of the units were sold in the Detroit area , so if you have any contacts there , start there. Web search car clubs in Detroit for MGTD owners. Also the Greenfield Village / Henry Ford museum in Dearborn has a research center that is available & has tons of info available for free. You actually have to contact them & make an appointment to get in , but it is not difficult. Looking on the web in the classified section of the Detroit News for issues in the late 80s & early 90s would also help. Just browse the Sunday classifieds for ads & phone numbers & don’t waste time on the daily papers , just Sundays.
Good luck,
Larry in Daytona,Fl. ( formerly Dearborn,Mi. area )