Thanks for all the help.
I've not solved the problem, but I managed to find a bth.inf file on the net which happened to have a lot of bluetooth driver entries. I stuck this in a directory along with all the correct driver files I assumed priovided the original Generic Microsoft Radio functionality. Then, after uninstalling anything to do with bluetooth, reinstalled using Choose location -> Have Disc, and pointing to that location. The Generic... entry and Microsoft Bluetooth... entry came back to the Device Manager, without ABE..., but setting the bluetooth device to receive a file, for example, still does not work. Although I can pair easily enough.
I'm going to try taking a complete copy of the system32 and sticking the bth.inf in there, on the guess that maybe there was another file missing, as the reinstall did not go completely smoothly.
I have another problem, which I'll post seperately, involving the example Bluetooth Chat working fine in Visual Basic, but not in C#... if anyone feels like taking a stab.
Thanks again,
Matt. W.