How did you work out it was the pump? Any visual indicators? Or did you notice it once you took the pump apart? I'd hate to go through all this work to find out that it wasn't even necessary.

I'm 80% positive my water pump has been done recently since this car has already had some major work (valve steam seals) done already.Not sure why they didn't just do the coolant pipe while they were there... I think the pump has been changed because the colour of the metal on the water pump is different to the rest of the engine that it's bolted to so it's definitely not the original unit that would've come with the engine.