Thanks for all the help Kiya. Much appreciated.
Yes, the first time I went round, I managed the teleporter gem, no problem. This time, however, even though I collected the gem, the dialog doesn't appear so that I can insert it - just 'leave'. That's my problemo!
I'm going to go back through to the act start yet again ... last time. If it goes pear shaped this time, then I'm ditching it.
On your list, the only quests uncompleted this time round are the Monks (no key anywhere), the teleporter problem (gem has vanished on me). I think I have done the rest, so should be OK. Provided of course the points have accrued as they should (must go and check my rating on the table) - as I mentioned before, I have had sessions where experience points have stuck at one value, and I've had to reload to clear it.
Where are the old Ultima series these days ... I cut my gaming teeth on those.
Morrowind was good too ... played that for over two years, and although I finished the main quest in the end, there were still lots of loose ends that needed tying up, when I finally decided to call it a day. That was the best of the lot, for me.