Get hold of the regs and stick to them. I found that when I posted questions I got some wonderful answers, however if I took the advice it would exclude me from racing.
If the car is use purely for racing you don't need an SVA, so don't worry about some of the requirements.
Get to a race meet as soon as possible. The last one of the season is Mallory Park this Sunday (not that far from you)! Just seeing the cars prepared will show you things that won't be covered anywhere else. (Like why they have aluminium 2l oil tanks under the bonet)
I am suffering from a possible change of direction. Do I go purely race, or do I go road, or a combination. I havn't quite finished the chassis, but I need to decide so I can buy the appropriate roll cage. It's a £400 investment that I need to budget for.
If I had my time again, I'd forget getting a donor and buy bits as and when. Reason? Well I have a garage with heater blowers, wiper motors blah blah that won't be needed. Secondly, the formulae is quite specific on engine limits, gearboxes etc. so you will find it hard to get a single donor with the optimum combination of parts.
1 last thing. There are about 5 people now regularly posting here who are in the same position. Any advice or suggestions you have will also be welcomed!