Hi, no, not the water pump, as I have just replaced that whilst doing the timing belt, this is the part that the thermostat sits in, before you put the “top” on, that has the pipe from the top of the radiator .
The housing has a small pipe from the side that is a “T” piece and is prone to rotting! 2 small pipes connect to it.
I don’t really want to take everything off again if I can help it, although I do know that everything should be easy to undo again!