posted this 18 December 2017
A monsoon pump would be ok for filling a bath. Although it's not ideal running the pump one ended, it will only be for a few minutes and a brass pump will cope with it better than a plastic pump. We have a Monsoon 1.5BT that would be suitable.
As long as you have a flow of at least a litre per minute under gravity, hot and cold, you can use a Standard (positive) pump.
I would suggest fitting the new equipment before purchasing the pump as some diverters are quite restrictive and may require a Universal pump.