My little repair shop man has tested everything that he can and has given me a two possibilities....
Either I have killed the processor - 80%
Or I have done something really odd to the Motherboard - 10%
Or Both - 10%
This means that my hopes that I had just blown the PSU are of no avail.
A replacement processor is about £25 on EBay, and the motherboard would make it a write-off and I don't think second hand ones are worth the hassle.
Budget will not allow me to spend £800-900 on a new system so I have to try the EBay route first.