Is anyone surprised?
Probably the easiest way to get in would be at VP1 (vehicle enterance by cargo). With the choice of limboing under the vehicle barrier or turnstile, I'm surprised that Keith Chegwin hasn't made a program about it
All you need are dark clothes and a bit of courage, and the airfield would be your oyster. How about a nice simple PIR detector covering the area which sets off a bell in the VP1 'hut' - I think Argos sell them for about £20.