Ok, that's sounds fine. I'll have a spare power supply so I could always use that and "trip it", otherwise I know plenty of guys who mess around with electronics and will have something compatible.
The only thing I'm a bit unsure of now is the radiator that I should get. Does anyone know for sure if either of those radiators in my above post would actually do a good job? Better than the BIX and H120.1 etc.
Thanks again!
EDIT: I asked the owners of the shop and the first shop has got back to me. Whoever said it was right - it's the DangerDen one. Is that actually a Chevette Heater Core, then? I can't find much details on this