Old Wombat built a Vickers Medium for this RAM theme.
It was a great build you can see
hereAs part of that thread, Frank said
The Vickers is looking good. I want to make one as an early APC. The interior kit looks interesting. Panzerserra Bunker built a Mk.II* for a client.
Having one in the stash, lets explore that APC Idea. Sorry Frank

Stealing your idea
During the early 30's the British were doing a bit of work on combined arms tactics. So what if, when the Mediums were retired and getting stored prior to being used as hard targets on a range, there was a line up against a fence and one Officer walked past and thought...
Wait.. how many troops could we fit in that and what if....... So three are pulled of and a bit of work done to make them a platform to further test out the armoured APC concept, following up on earlier work on the Mk IX type tank at the end of WW1.
It would be squeezy, very squeezy and very crouchy I think, but troop comfort is quite often not often top of the considerations at an early experimental stage. Probably 6 soldiers tops the way I look at it.
I took the Vickers Medium Mk II kit to the last weekends "Modellers Retreat" build weekend and started the build
First up, the Hobbyboss kit is quite nice, a simple build and not a zillion parts, goes together swiftly

First up lets block out the bits that we need, like the engine compartment and move the fuel tank to allow better egress for the onboard troops

That then covers one of the MG ports, so decided to move them to the existing doors. To my mind the thinking would be that these MG would still have a use with the mindset of the 30's

Enlarged the rear hatch to have two doors. I think that the idea of a ramp would be too advanced for these early experiments.

I have to revisit the drive train a bit as it is not even really clear on the IMA interior kit pics what the drive train is or where it goes. So a bit of internet rummaging will be required for that, then look at what might replace the turret space in the hull top