Andy I will need to do some scrambling about but basically the boiler
is on ground floor (kitchen). The pump is under the ground floor - I
think there is a motorised valve down there as well. The hot water tank
is on the first floor. The expansion tank is in the loft one floor
above the highest radiator.

Sorry it is very general but as I say the rest I will need to refresh
my memory with regard to the rest.

Al.