Hello!

[Grant Bowker]

I don't have answers to all of your questions but may be able to help.

Yes, there was an Airportable variant of the 60 cwt lorry.

The curved cut in the step is something I have seen on other trucks but I do not know why it was done, except possibly to use pieces of metal that would otherwise be scrap. The curve on the steps I have seen are all similar so it must have been a planned thing rather than just using any old pieces of scrap that they had.

I'm quite sure the spring, bracket and tie strap are to provide tension to keep the cover in place over the observation hole in the roof and also permit it to be removed quickly when needed without loss.

I had not seen the depressions in the door on larger trucks but have seen a late production HUP with lubrication information on a plate in one door (and I think a wiring diagram in the other).

There has been discussion of the engine cover differences before with people saying they believed the version you show is to allow for the wading equipment.

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On edit: I am at work, started to answer befor Phil's reply but had to pause to do some work. At least Phil's and my answers don't disagree badly.