Hi Geert
I have installed Debian on a different machine using the suspect machines hard drive and all went well.
I also installed Ubuntu Warty Warthog Release on this suspect machine using it's suspect hard drive and that worked ok.
I am thinking that it may be worth checking what driver / module is being used for my disk controller as Ubuntu is debian based and seems to work fine? To that end I shall have a look and see.
You can close this bug report if you like, my machine is very old and I doubt if anyone else is trying to install Debian on this hardware. I will just try to figure out a workaround.
Many thanks for your help
Nick