How to choose shower valves

[MichaelD]

I have gravity fed hot and cold water supplies to my bathroom via 3/4 inch pipes. The distance from the top of the cold tank to the shower head position is 6 feet. I want to fit a thermostatically controlled mixer shower over the bath and also fill the bath from the same wall. I don't want taps on the bath itself. First question is do I need a pump? Second - is it best to fit a mixer at chest height with a diverter valve below and then a bath spout just above the bath or are there alternatives. All advice much appreciated.