Well I've had a look at The New Rebels site and it talks about Hex editor or IDA Disassemblers.
I extracted the PCI Option to a .rom file. I tried to then load that into mmtool but it didn't like it (Error loading ROM image (100000h)).
I downloaded IDAFree, but to be honest I'm out of my depth here.

I naively thought that these SATA drives would be plug n play... Guess I should have done some research before buying them!
I'm getting to the point where I have to admit defeat. Guess I'll have to hot-plug the drives once the OS has loaded. This means I won't have RAID 5 as intended and will have to span the partition. Will Vista do RAID 1 (mirror)? Or I buy an add-on PCI card. 2 port are cheap enough but to do RAID 5 its £100s.
If you have the time and relish a complex problem, let me know if you figure it out!
Many thanks for your time so far....