Have a look here….loads to have a go at!

http://www.allenby.info

Pic below taken at crash site of a Blenheim Mk1f. Could this be part of the seat from mid-upper?

Presumably it could never be made serviceable again?! Be good to see it bolted on the back of a JG71 F4!!
In all seriousness, I’ve seen it up close and personal, and it’s s*dding huge!

The Canon 100 – 400mm is a nice piece of kit, I got mine off an ebay seller as well, Scottish bloke whose name I forget… I can dig it out if you like.
I’ve not tried the other lenses you mention, but the Canon 100-400 is better spec’d in my opinion because of the IS. At 400mm zoom (+ crop factor) you need fast shutter speed to stop camera shake, but because they only open up to f4 or f5, you’re seriously in need of some light from somewhere. Bumping up ISO helps but degrades quality….IS allows you to slow down that shutter speed and claw back some light.
However, this is all just IMHO…I’m down at the bottom of the learning curve, lol.

We had the Avro factory in Leeds, complete with duck pond and cows on the roof!
Also, I read somewhere that the Swiss had an aircraft factory during the war that was mounted on some kind of rolling system which enabled it to be retracted into a mountainside if an impending raid was suspected. One has to wonder what the point was…if the factory worked just as well when tucked away in said mountainside then wtf was the point!!?? Keep it in there!!