Thanks for the reply.
My /etc/resolv.conf looks like this:
however the same problem exists - mail send fails with same error.
However now dig mydomain.com MX is returning MX records instead of timing out...
But mailq returns "name service error for name=gmail.com type=MX: host not found, try again"
If I change domain of outgoing in MAMP Postfix to imap.gmail.com, same error.
So we've got somewhere in that it can return dig MX now...
Thanks again in advance.