The figures shown are definitely not WW1. HOWEVER, the photo Model Hobbies is using is Strelets' photo. So I'd say there is still the possibility that it is a WW1 crew in the box.
If you look at A001 and A004 they have the same crew figures, British WW2. A002 and A003 have British WW1 in soft caps and American WW1. So there is a space for British WW1 in tin hats, maybe A001 has them.
Would be good if Strelets updated the A001 information.
BTW, without wishing to thread hijack, all four guns, A001 to A004, were used in WW1.
re A001 & A004
The figures are WW2. The ORs wear the WW2 battledress ( blouse), anklets, web equipment etc with some wearing leather jerkins.
The gun on the box art of 004 is in its WW2 guise with pneumatic tyres ( photoshopped in this instance)though the masters ( computer pics) show the WWI guise with traction engine wheels.
Time will reveal all.
Some of the 6 inch BL MkVIIs(A001)( and earlier marks) were used as coastal artillery on pedestal mounts.
There is a photo of King George VI inspecting what looks like a MkVII(or XIX) in 1941. It looks as if it is part of the coastal defences and has its traction engine wheels with wheel scotches etc basically as it was in WWI.
Would make a nice diorama.