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.