Thanks for the tip, but sadly I don't have admin rights on either of the networks in question and wouldn't be able to reconfigure anything...

I can manage it, fortunately, by using the one finger of my left hand on the right-hand Alt key and using the right hand to bridge the right-hand Ctrl and delete keys; it took me an embarrassing while to work out that you could use the other set of keys, though!

The doctor prescribed anti-inflammatories this week, which I hope will help.