I'm using Gmail to read mail from a couple of other accounts that I've got, I've just added the accounts in the Gmail settings under 'Accounts and import'. But I haven't found the ability to add IMAP accounts, only POP3. Anyone know if this is possible?
Gmail cannot read mail from external IMAP accounts.
Instead, you can set the external account to forward to Gmail, or just use POP.
If the external account supports IMAP, but not POP or forwarding, you're out of luck.
I'm not aware of any such email providers.