Add up all the bits Ppruners said should have been included, subtract a few bits that could have been left out, divide by 90, and see what you have.
Actually demonstrating the Lysander, still much a secret operation, and you have an educational bit for Joe Public, ditto John Tye and QRA.
The ATA, the photo device and the Bomber Command vets give the clue to the production. It was people centric not loads of old film clips.
BZ