Well it’s taken me days to find the solution to get postfix, saslauthd to work with a remote imap server.
It turns out that the key is saslauthd runs chrooted and needs to look for it’s socket file in the chroot jail in /var/spool/postfix/var/spool/saslauthd. Once I symbolically linked that file with /var/run/saslauthd.magic happened.