Another HAS story. II Sqn Laarbruch, about 1981.
The Mk1 HAS was equipped with clamshell doors. The door motors frequently failed but they could be pushed open or closed by a couple of blokes. On the inside of each door there was a 4" diameter steel pin which dropped into a hole in the floor in the closed position. One night shift, the lineys pushed both doors shut from the outside, only to discover the wicket door was also bolted closed from the inside.
It appeared that there was no way to get inside the HAS (which had two Jags in it) There was a circular hatch in the side of the HAS, about 12" diameter, for passing through a houchin cable but it was too small for anyone to get through. Then someone remembered that some ATC cadets were at Laarbruch for their summer camp. Someone was dispatched to their barrack block. They turned out all the cadets (at about one in the morning) and took the smallest one back to the squadron and shoved him through the houchin hole. The cadet unbolted the wicket door and the HAS was liberated. The cadet was returned to bed but the next day he was given the VIP tour of the sqn with lots of cockpit time.