I don't know for certain who made these films, but I seem to recall Dr Whiting (@2.20 in the film) being involved in the Film Club?
Before the school went comp in 1969, I (obviously) was in the blue building - the desks and all the décor were in pristine condition.
Occasionally, a girls was required to take a message to the boys' school and when it was my turn to go (dreaded it!!) I saw all the desks were old, ink-stained, carved into, and décor was shabby, and smelly - the difference between young ladies and frogs, snail & puppy-dogs' tails !!!
After going comp, as you say, we had to walk between buildings between lessons. The terrain was ok but obviously we got soaked when it rained!
The forms were 1E 1G 1A 1P etc (Excellent/Good/Average/Poor). The top stream did O Levels and CSEs, the G stream just did CSEs. The A's often 'ended up in the typing pool'! Girls weren't allowed to do Physics/Chemistry (those were boys' subjects), they could only do Biology as a science subject.
Prefects in the Girls' School wore lovely tartan sashes, but when I got to be a prefect in my last year, I guess they were short of money because they cut all the sashes up and we just wore a piece attached to a prefect badge! Still got my prefect badge - and my school reports AND leaving report!!.
(now I'm rambling too much )