[raymo]

Once again thank you all for your input. I managed to get my hands on
another handset cable, and it froze up again after 30 mins. of random
button pressing. It has occurred to me that when frozen, not only do
commands to the mount stop working, but all other buttons don't
work either. I assume that looking through the the NGC list, or the
Messier list, for example, takes place within the handset, and has
nothing to do with mount, and therefore the problem must be within
the handset.
I'll ring the supplier tomorrow and see if it is still under
warranty; and I will get a Bahtinov mask as well.
thanks again raymo