As regards applying hand brakes; Some years ago, late 1980's when the activities at Bovington was held at Gallows Hill there was an incident concerning me. A Grizzly had been parked up on a slight slope where the public could come a have a close up look and talk to the tank crews. Suddenly I noticed that the Grizzly started to roll forward, quickly I sprinted forward, dropped into the drivers seat and brought it to a halt. The owner of this who I cannot remember (are you reading this sir ?) stormed across and remonstrated with me for being in his tank ! This person had without doubt failed to leave his tank with brakes applied and in so doing had endangered the public.