Hi
Its definitely uparmoured, vision blocks, extra armour and new drivers seat (not sure of relevance of last one). It looks like it may once have been RFC, I'll post a couple of pics and would be interested in your oppinion.
It certainly started life as a mark 2 (2 piece turret) APC, the uparmouring also includes a metal skirt around the bottom of the turret (presumed that was to keep out fire bombs etc).
Will come back with pics this pm.
Cheers
Paul