Thursday has arrived - nothings changed. Still have folders with a # that I can't access.
Same for me, I'm sorry to say.
I have no confidence whatever in BT's ability to fix this, and even less desire to waste my time on the phone to them. As a result, I shall download Mozilla Thunderbird and do the job myself.
I'll post up the results.
Well, thanks to Thunderbird (and to the "sage" who recommended it), my folders are now legal and in good shape, and all my invalid #-folders are gone.
It was a bit of a battle, and several times I got the "Not responding" or "Script not running" messages.
Being ultra cautious, I started by creating a set of folders to receive the contents of the #-folders. Then I copied the contents across, folder by folder. And finally, I deleted all the #-folders. This step moved them as sub-folders under "Deleted". One odd thing was that, when I then logged into BT Mail, I could display the contents of these "deleted" folders, even though their names still started with #, which I was unable to do when they were top-level folders. I can't explain that.
All sorted. A young lady from South Wales (Casey - I may have spelt it incorrectly) has arranged for it to be fixed. BT have replaced the # character in my folder names with a - character. All working now. Thank you Casey.
Glad to hear it's fixed. Well done, Casey.