Fascinating prog---and like others here agree with the rather ludicrous slot time.
Loved the bit though, when they were towing the prototype Valiant out of the shed--lots of guys waving people away including the one in the flat cap--and the big cloud of smoke from his mouth !--magic !.
Just one query though. I saw one shot of a Vulcan getting airborne with airbrakes extended---normal practice from a roller or not ?.