That's exactly what the issue was, Bob.
If you type my username in a simple text editor on a Windows or Android machine, you get: Slimbloke
'H
'
If you do the same on an iPad, you get: Slimbloke
‘H
‘, and for some reason, after the update the BBS now doesn't recognise iPad apostrophes as apostrophes, for login purposes.
Fortunately, the workaround se1eagle suggested works.
