Update time - no cables arrived as yet so I scrounged a PSu from someone which had only 20 pins and was only 240Watt BUT it booted up the computer. It looked good for a minute and then ------------ BSOD. So, I guess we can rule out the PSU. Ive left it running to see if it has any more BSOD's but I would be surprised if it doesnt happen again. Thermal paste ordered and new MoBo will go in as soon as it arrives.
Fingers crossed. Regards. Paul