The Mark I Supply (MT72813) looks great. Because it has the prefix "72" is it 1/72 scale (based on the Emhar)?
I hate to say it, but the rear armour on MT72806 is not correct - on the real thing the top part had less slope and was a bit smaller, so that it did not block the fuel tank filler hatch:
They look very good - although the Mk IV's Hotchkiss mg's may want to be changed to Lewis's as Hotchkisses for the Mk IV came fairly late (I only recall seeing one image of a Hotchkiss armed Mk IV in France, and that was 1918). If you want some images and dimensions of WW1 stowage, petrol tins etc for the Mk I kit I can help with those