LewisS you might find this of interest. It's part of a letter I've just recieved from BA Connect regarding my application for a Security Passes on the IOM.
Background Checking - Criminal Record Check
Due to othe nature of business conducted, it is considered that security of the Airport is a matter of national security. Therefore the provisions of the Rehabiliation of Offenders Act DO NOT APPLY and details of all convictions, cautions, reprimands, binding over orders etc, must be declared.
I think this is probably exculsive to the Isle of Man but non the less something to think about.
All the best.