Mark,
Thanks for the help. I was definitely stuck for a while.
Earlier this evening I got off my arse and searched a little harder and found what I needed on one of the mandrake support sites. All working now.
Essentially, there is a file /etc/rc.d/rc.local which is the last init file to be loaded - therefore various useful bits and bobs can be stuck on the end and they will over-ride what has gone before.
Not elegant but it works. Not the debian way I assume :)
I did ned to edit some of the other files as well and I was particularly pleased to see that according to the hardware database on the mandrake web site, my card should not work. So one up!
Syd