Sorry - they have obviously changed their driver packs making it even harder to sort out the problems their drivers cause by not providing the removal tools on the CD any more.

Good luck!

Did you bring a laptop to see if it would respond to/detect the printer? (HP did make a few self-bricking printers)

No, I wasnt really prepared because I didnt go there from home.
I'll be back there later in the week and will test it that way.

Hadn't seen anything further and just wondered.  Were you able to get it working?

yes,
apologies for not reporting back - it did turn out to be cable related.
I havent tested it since, but I think the USB cable was screwed - I think it may have been put in one of the other sockets (network or fax). The problem seems to have been complicated by the fact it was a long (3m, - 10 feet or so) cable. I replaced that with a shorter usb cable attatched to an extension. This had worked previously (and also works since) but the printer was not recognised with it. I rang HP and they were saying they'd replace the printer (they didnt seem surprised) but they guy did ask me to try with a shorter cable first. They got me to do a reset on the printer as well - it's possible that helped too. When I moved the printer nearer and used a shorter cable it worked.
I really should have fully checked out the cable possibilities before anything else, but I didnt - live n learn...

So, thanks to all for your help!