Thanks again for the advice, I believe I've got the Ethernet card working now.
I removed the driver that was on the card (since it was flagged up as in error anyway in device manager) that Win98 appeared to put on. I then delved inside the PC, found it was a 3COM card with a part number, searched google, found the 3com website which allowed me to download the driver. Put it on, got Win98 to use it and it now looks ok in the device manager. Sorted (hopefully!).
Now for the call to NTL to get broadband set up on the PC before getting the wireless kit.
Once again, cheers for the replies

. Something tells me that I wouldn't have had the answers to my questions if I rang the NTL sales team!