All sorted and shes back on the road and the head gasket seems to have escaped failure this time.
I found some very interesting stuff by doing the job myself, and needless to say i wont be using the mechanic that did the previous cambelt change again
Upon inspection i found cheap Chinese auxiliary belts, the cambelt tensioner was setup incorrectly putting far too much tension on the belt which explains why the pump failed so early and the bearing on the tensioner was as rough a bears derrière
The timing was a tooth out on the crank, and the pump had been fitted with black RTV sealant rather than properly cleaning out the aperture the pump fitted into. The lack of circulation was caused by the fact the water took the path of least resistance and was leaving out the side of the pump from the failed pump seal rather than actually going round the water system.
It now has a new 82c PRT thermostat, Genuine MG Rover timing belt, tensioner and water pump and is fitted with quality auxiliary belts (land Rover & Gates branded) and filled with G13 Si -OAT antifreeze/coolant with de-ionized water.
Its booked in for MOT next week end, i just hope its all been worth it as if it fails on anything major i'll be gutted. I'll be checking my ZRs engine next week to see if hes made the same mistake on that.