how to get more water pressure from a mixer shower. on a gravity feed system

Alter height of cold water feed tank. Fit water pump. BOB OF B.R.PLUMBING SERVICES>

pop a pump in ............or , if your boiler is old and un efficient then fit combi boiler save money in the long run ,hot water at mains pressure at every hot water outlet, as many hot showers as you like when and as long as you want no hot water running out and as a fully pumped system far more efficent and you saving the enviroment in the process regards jon

fit a booster pump (salamander ct50) your problems will be over!!!. DONT fit a cheaper pump, you will just have to replace it later on.