How do I configure DNS to forward mail to A&A hosted email.
Configure MX Records as follows
mydomain.co.uk. 300 IN MX 10 mydomain.co.uk.incoming-mail.co.uk.
mydomain.co.uk. 300 IN MX 20 tertiary-mx.co.uk.
(Set TTL to taste. Shorter is probably better when you're first setting this up!)
If you want to set up an SPF record, please see the SPF Record page.