Hi Skaero,
Yes the log files are writeable - they contains various unrelated entries. I was logging IMAP for a while but nothing seemed to be out of the ordinary, successful logins from Gimap e.t.c. but RoundCube would still timeout.
Forgot to mention, mysql is on local machine, IMAP is obviously remote. But given that ti works fine for other users, I can't think its a problem with connectivity or delayed connections.