I understand your concerns, but the same applies to most of the electronics teardowns (cal potentially lost, risk of damage, etc.).
Not even close.
Most cals are electronics of sort sort, and even the ones with pots, you have to deliberately poke at them and turn them with a screwdriver to screw them up.
It is very rare that a pure electronics product needs a re-cal after a teardown. The only example I can think of would be a really high end spectrum analyser that (in theory) might have it's noise floor changed if you don't seal the RF gaskets back up right. But even then, it's just "down in the noise", it's not going to put the thing out of whack.
It's just not a good enough reason for me to not have at least a cautious look, especially given the fact that Dave would encounter substantially more goodwill and understanding than any of us if the worst should happen an the unit require realignment at the factory.
It's just so unlike Dave not to go there, who knows, perhaps we will still see more on this topic in the future.
I asked them, they said it is unlikely I'd see the most interesting stuff without a reasonable possibility of stuffing up the alignment, which would require expensive shipping back to the UK from Australia and back again. It may or may not be true, but I believed them. After being specifically told that, I didn't want to be a dick and screw it up, I bet you would have done the same thing.
They said they would look into an old/broken unit I could have for a full teardown, but nothing became of that.
You can tear your one down for us all to enjoy, we are looking forward to it. Feel free to say "I told you so". But that also works both ways.