Have you heard the one about the world renowned aerobatic team who wanted to park on the western apron at Bristol so they could have access to the ATC facilities but were told that they couldn't use the security gate beside the tower because they didn't have the requisite security passes? So they parked on the southside instead, where it appears, DfT aren't worried about security.
Dontcha just love the Dept for Tw*ts, sorry, I meant Dept for Transport
Noisy, this would be because the Southside is in the Controlled Zone as opposed to the Restricted Zone (which requires a valid pass and full search). Bottom line, no doubt, was probably avoiding paperwork!