Morris FAT C8 body types

[mudeng]

I am currently engaged on a modelling project and need some clarification on the various body types.

From the various sources, I have identified the following:
MkI:
Hump backed body.
Glazed panel on drivers side only, plain doors without glazed panels.
Enclosed roof.

MkII
Hump backed body.
Glazed panels, drivers and commanders side.
Glazed openings on both doors.

MkIII
As MkII but with canvass covered opening in centre roof panel.

MkIV.
Square body, with canvass roof, towed the 17pdr.

Is this correct ????

Also at which stage were the front springs changed from being under-slung, to over the front axle ?????

Are there any census numbers to denote which marks were which ?????

I know this is a tall order, but any help would be of value.

Thanks
George.