In the photos, I see the blanking of the battery box wiring holes, and the rear panel, and side panel bren mount holes, which are factory blanked by riveting. This was a standard production method. This is why I say she was a mortar carrier. I would doubt that any Scouts were factory converted to MkII Universals. Scout production finished about 1938, and the first MkII Universals were produced in 1942. By this time the Scouts were lost at Dunkirk, or had gone to North Africa. Aside from that I can only think of one difinative Scout feature that MIGHT have survived in a factory rebuild. That would be the bolt holes for the air ducts, which on the Scout are curved, and on a Universal, are straight.
I believe that all other Scout features would have disapeared.
I cannot see a factory halting its systemised. production to pull one old Scout to bits to rebuild it as a Universal MkII. ( I Imagine also that had this been done, then it would have been renumbered)
Would they have stripped the carrier to the point of removing and replacing the gunners front plate, the hull division plate, The rear plate (that started this thread) Which in the photo looks like a standard factoy Universal installation. the side armour on the left side. etc. etc. etc.
One would have to consider the order in which parts were riveted together, and then the difficulty of doing some of those operations in a different order.
I am not trying to poke you in the eye Shaun. I am saying (from my limited knowledge) that it is highly unlikely, and that because you were un aware of what the differences between a standard Universal carrier, and a Mortar carrier are, that this was the conclusion that you arrived at.
Pictures are Philip Hastings Scout hull, and one of the Air ducts common only to Brens, and Scouts. the last picture shows a Universal carrier air duct arrangement. Note in the Scout there is no armour plate at the outer upper corners, that is in the universals.