An Air Transport Pilot Licence is completely irrelevant to gaining an entry to the Forces - I know having done both.
The RAF - or any other of the Armed Forces - look for more than just somebody who wants to fly for money. It is a career that they offer and they are unlikely to accept applicants that are less than passionate about being a member of the armed forces.
This may - and often does - change after several years of service and then people who want to stay flying will often then study for their ATPL. The CAA currently recognises some of their skills by reducing the number of subjects required for an ATPL.
Anne
