Welcome to the forum David.
I'm also quite local (Durham) and will be building in a single garage. I've bought a chassis and donor parts off a guy who doesn't have time to finish the build so managed to get quite well set up.
I've posted a link on this section last night about someone selling donor parts, the only problem is the distance, I think it was somewhere like essex.
Also, Birch Brothers in Yorkshire will supply a full door vehicle pre-stripped. Can be quite expensive, about £500, but all the works been done for ya.
The final option is to just keep watching ebay. If you look in the car section, car parts, then scroll down the list of manufacturers names until you come to kit cars. That section's full of useful stuff.
Once again, welcome to the forum, and if there's anything I might be able to help with, just gimme a shout.
Alan
p.s.well worth a visit to Saturn Sportscars in Hartlepool, really nice guys, can supply everything roadster related from an engine mount to a full car, and a ride out with big Andy (spud69) in his roadster is a real eye-opener
as to what can be achieved on a budget. Just take a spare pair of pants!!