Sounds like a challenge ...
Seeing any replica WW1 tank moving around is a Good Thing, and it's even better if it's a full-sized one. An illustration of Real History, and a demonstration of how the tank has evolved over its 100-year history.
These look pretty good. The only obvious 'flaws' I can see are the lack of rear armour over the fuel tank (much debated on this forum !), which leads to the design of the unditching rails at the rear being all wrong (if they should be there at all).
Auld Crusty looks to be using the original Solomon camouflage scheme only seen on the Mark 1's, although the light blue makes it a bit too 'Caunter'.
Spring Chicken is in mid-1918 format with the stripes, but should probably be in chocolate brown (whatever exactly that was !) rather than green.
As for names ...
Auld Crusty is not unreasonable for 1916, Arras in 1917, and possibly for the Gaza Detachment. I think the Tank Corps in WW1 stopped at L Battalion, so no
Spring Chicken (which strikes me as an unlikely name anyway - Battalion Commanders weren't
that relaxed !).
And finally, Stephen, they were never described as 'wagons'. Original accounts refer to them as 'cars' or 'buses', without any differentiation between Males or Females (a WW1 historian once tried to tell me they were called 'Dogs' and 'Bitches', but I've never seen that anywhere so I don't agree).
Enough to be going on with ?
All the best, and thanks for putting them up,
Chris
Resident WW1 Tank Expert
('Ex' being a has-been, and 'spurt' being a drip under pressure)