Replacing a shower pump,Pigletjohn perhaps!?

[justaweeone]

We have a Mira pump located in a bedroom cupboard that used to feed three showers.However we replaced one shower with an aqua lisa that has its own pump located in the loft above the shower.
The Mira pump is now leaking slightly and does not work that well ie cutting out so we want to replace it to boost the other two remaining showers.
Any recommendations,tips etc gratefully received !