I have set up a couple of email sub addresses, but I can't work out how to get my IMAP client to fetch emails from them. It seems to require my BT login to log in - it won't accept the sub-account email address and password. But the main account only fetches mail from the primary email address. How do I do this?
In your email client you need to "add" an account. You then set it up in the same manner as you did for your primary account but on this occasion you obviously use the email address and password for the sub-account(s). You need to do this for as many times as you have sup-accounts that you want to access.