Thank you for your help.
Some great ideas there. I have put in a bid on the old school one with the adaptor attached.
Not willing to pay over the odds for postage from Aiya Napa for that one. Also not willing to pay for the RJ45 cable one as my electronics skill is limited and fiddling around with an RJ45 adaptor cable in the hope it will work with a modern USB port computer is really beyond me, as I'm not sure I could get the parts.
What amazes me is how MUCH these keyboards are going for on Ebay! If I'd know this, I'd have grabbed a few from my old office years ago (they had loads in a cupboard - the only keyboard to cope with seriously hard typing) and flogged them on Ebay.