OK – I have managed to DELETE the NOTE in its entirety (using my phone) so as soon as I get the site access back on the PC, I’ll put the text of the note I edited in Notepad into a pdf file and upload it as you suggested Nigel.
So my problem is over – I think – but do you think it would be a good idea to have a tool to check for invalid characters in NOTES given the rather severe impact of hitting one – if indeed this was the cause?