Many thanks for the info David. There can never be too much!
I actually had the water pump replaced at a garage today as although I am pretty proficient at car mechanics, I don't have a car lift so access underneath was somewhat limited, even when jacked-up and supported by axle stands. As it turned out the pump was very stiff and the guys at my local trusted garage said it was very hard to remove due to limescale / mineral build-up jamming the removal. I don't know if this is a result of using tap water, a mix of coolant and tap water, or a mix of non-compatible coolants by a previous owner maybe. But they eventually managed to remove it after a struggle so a good decision to take it there after all. Not sure if the limescale/ mineral deposit will cause long term problems or not, but not sure what I can really do about it. It never seemed to cause any problems overheating so fingers crossed.
I'll try contacting the companies you suggest for a refurbished dummy aircon pump.
Oh, and mine's at a very similar mileage to yours!
Many thanks again for the advice and good luck for your MOT.
