looks like knackered fan switch. It should be kicking in at 94 or 95 degrees iirc.
Was the thermostat changed also when the water pump was done? Could well be the thermostat was on its way out and by removing it and re-using it, it packed up completely.
Id first change the thermostat, then flush the entire cooling system and stick new coolant in there. If it still runs hot then I'd look at replacing fan switch.