Ok, thank you.
So what I have done is set up the Gmail account in Aquamail then attached my normal IMAP account in Gmail (web version) so it can now be read in Gmail on the web.
Now, my IMAP mail comes up in the Gmail account in Aquamail.
Is this what you meant?
So, looking back at my original problem, why can I now suddenly not receive messages on my IMAP account? Is your suggested fix normal, or is it simply a workaround?
Cheers.