Two hours
It took 37 minutes on hold before being able to speak to someone - who couldn't help. She pointed me in the direction of someone else on a different phone number - more waiting. Eventually, after over an hour of telephone tennis I got somewhere useful.
The worst part of it is that the @btinternet.com address my mother would have needed to use in order to send is that of my recently deceased father. Trying to explain that I didn't have a password (because it was my late father's account, not mine) and that I didn't want to reset the password (because that would mean me driving 600 miles to change it on my aged mother's machines) and that I certainly didn't want to be using the address of my late father caused them some bother.
Eventually a nice Scottish woman called Elaine said she'd cracked it. We shall have to see.