Thanks again Diane. Just another couple of questions, if you don't mind. I'm not in front of the pc right now so I can't be definite about a few points.
The folders used by the POP3 account are not normally removed from the folder list, as they are also used as the default calendar and contacts for the IMAP account.
It sounds like the POP3 GMail account is only a minor one.
The pst file is not deleted from the drive and can be opened in Outlook.
Ah, never thought to look in the archive to see if there was anything left. So each of those two accounts will have a matching pst file in the store location?
...two choices: remove the accounts and open the pst files using File, Open, Outlook Data File or export them to a new pst My preference would be to remove the account and open the pst files.
So we could remove the accounts from the Outlook interface altogether, but they'd still be accessible any time by opening them as you've shown above?
Note that it's common to only download IMAP headers and unless the mail in the imap account was downloaded completely, you won't be able to use it.
How can I tell if the mail was 'downloaded completely'? The mail all concerns commercial house-building activities, so it's all essential stuff, and my guess that a lot of it would have had attachments. I think the account would have started off as a POP3 but I believe the owner had tried to simplify his rather complicated mail situation (several different ISPs in several locations) by using the zoho 'add-on', if that's the correct term for it. He's now dumped zoho for the same reason - it only made things more complicated.
So, for now, he needs to be able to access the sent and received mail in those folders. Incidentally, this entire situation arose because a staff member left the firm and his laptop is now being used by his replacement.
Once again, thanks for your invaluable input