I have been summoned! (TBH, I wasn’t — for some reason, I didn’t get a notification about being @-mentioned, I just happened across this topic.)
No, I’m building an M32 TRV (Tank Recovery Vehicle), the one based on the M3 was the M31 TRV.
I think the posts above are on the right track, but in my opinion, the intention seems to have been to build a Grant ARV:
View attachment 460315
or perhaps an M33 prime mover:
View attachment 460314
The reason being, there is a hull floor with the transmission is from an Italeri M7 Priest (or Priest Kangaroo) kit, which kind of points to an open-topped vehicle on which the transmission would be visible. All of the M3-based recovery vehicles had a turret, except the British Grant ARV, and with a turret in place, most of the interior of the tank is obscured, especially the driver’s compartment (see
this model). On the Grant ARV with the hatches open (the twin Bren mount was far from always fitted), and on the M33 in general, the hull interior would be very visible, though.
This also fits with the Sten: that would likely have been carried in a Grant ARV, and speaks against an M33.
If you want to complete the model as a Grant ARV, I could scan the relevant parts from the old
Airfix book
Lee & Grant by Ken Jones and Peter Chamberlain (or you could buy a second-hand copy there
), as that has a section about converting the old
Airfix kit into a Grant ARV.