Thanks for the info keef66.
Your link doesn't work or the cards have sold out. However, I did manage to find a Sparkle PCI-E 6600 (non-GT) for about £40 click here. Usual price for the PCI-E 6600 starts around £70 I think.
I didn't know Misco sold items at such reduced prices. Just found their "liquidation stock" section - that has a whole lot more than just graphics cards - click here.