Almost Mike, though I’m more familiar with and the larger A2 (ish) format diagrams with three views – front, plan and side elevation with a very brief description, commonly seen on line hut and crew room walls. These don’t have a blanket AP reference, rather they are individually numbered (4 digits) so each is “Air Diagram XXXX”

I would be interested in having a peek at the 4280’s all the same, could be a new branch off the collection policy!

Thanks for taking the time to bring them to my attention, much appreciated 🙂