Ah! Semi success doing that Chuck!
I basically gave the folder the permissions set out in your link, then copied the contents of that folder into a newly created profile in Thunderbird. I then dragged the TEBE .xpi file into the extensions/add ons part of Thunderbird, restarted and was then prompted to enter my GMail and Hotmail passwords. So far so great.
Thunderbird now sees all my email accounts.
Strangely however, the AOL email has returned with all it's sub folders and old emails intact however the GMail and Hotmail have downloaded the latest emails but I don't see the sub-folders I used to have where I saved emails in my hotmail account. This is probably the most important issue for me to resolve as I've saved lots of receipts, software licences/keys and other important emails there.
When TEBE looks for the 'local backup to restore' it looks for this type of file -
But there seems to be none of these files in my backup folder.
Thanks again for your help with my issue.