follower: Thanks for the pointer to FastMail; I'll certainly look into that. Their free service obviously doesn't have the features of Port995, but for a small one-off payment it seems I can get a decent service.
I haven't quite decided how I'm going to organise my e-mail yet. I need to be able to pick up new mail on the move, but I keep a fairly large archive of past mail at home. Ideally my home server would download new mail from my IMAP server, but leave a copy there, without touching the 'New' flag (so it will still download mail I've read via the Webmail interface). I can't think of a way to do this (I don't think Fetchmail supports this - it uses the 'New' flag to mark whether it's already fetched a message). I believe Fetchmail can do this with POP3, by keeping a list of message UIDs it's downloaded - anyone know whether you can do this with IMAP? It wasn't possible last time I checked.
I might have to settle with accessing my INBOX folder via IMAP across the Internet from home - not ideal, since my connection is fairly slow.