Greetings Raymond
Thanks a million for your always amazing advice. It was quite an exercise but now all the addresses are combined in the one file within Thunderbird. Unfortunately, I made some kind of mistake when I was importing the new address book into Thunderbird and now I have 2 Personal...ssBook folders in Thunderbird. When I saved the amended book in Excel I misread the name and used capitals for the "ss" part of the name. I changed it within Thunderbird hoping a miracle might occur - I suppose it helps if you believe in such things - but there seems to be no way of deleting the original and now empty Personal...ssBook. I guess it doesn't really matter as long as Thunderbird doesn't start saving any new e-mail addresses in the empty folder - but, of course, it will. I did perform the import function within the Thunderbird Personal...ssBook but it would seem that, once again, I have performed another of my amazing feats of getting it wrong. Anyway, I'll try a few things and see how I get on. If you have a suggestion I would be delighted to hear from you.
Best regards
James