37x94mm identification

[earni74]

ths 37x94mm round is still baffling me, it has a typical British crimp on the case, VSM stamp on projectile between the bands, the fuze, the groove at the top of the fuze is not deep enough for a screwdriver and would not attempt to use one, there is a number 4 (very small) stamped on the side of the fuze, the base of the case has ink markings in (iridescent red) but cannot make out what it is, the case primer is unusual (see photo) lastly, the stamps on the base of the projectile is strange

Any info appreciated

 

[ron3350]

It looks like a normal Vickers 1Pdr with the fuze top polished a bit so the fuze slot is shallower than usual.
The case red marking may be the clue to ID but any projectile base markings would not be seen as they are inside the case.