Dave, Thank you very much for posting these images!
In fact one of my long time projects is a Mark I Tank from September 1916 crossing a German trench at the Somme and in fact this awesome work you posted here gave me the inspiration (especially the officer firing in total despair his Luger at the beast). That’s a very strong and impressive scene in my opinion.
Oddly the placing of the Minenwerfer doesn’t explain itself for me. The Minenwerfers (in this case it is a 17cm one I think) were placed in the first trench lines, but always in a widened, special area where the crew (6 men were necessary to man this guns) had enough space to do their job. This is obviously not the case here. It stands in a trench of normal widths. And besides of that the wheels are still attached to the Lafette which made it impossible to fire the Minenwerfer. It could be the case that the gun was on its way to its placement when the tanks broke through, but then the wooden beams for manhandling the Minenwerfer would have to be there. I am sure the makers of this diorama here had their certain reasons why they placed the Minenwerfer like they did, I simply cannot understand what is going on with it.
As soon as I am home from holidays I will post some in progress pics of my attempts to show a 25cm Minenwerfer in a frontline trench.
Best regards
Andreas