I currently have a really poor shower, that constantly keeps showing lower pressure light, the only way I can start the shower is to turn the cold water tap on and off quickly and the light goes out and I can shower, although not much of a shower pressure. Would it be the shower or mains pressure ? Would it be easy to re route the pipe work from mains supply to gravity feed from my cold water tank and fit an electric shower with built in pump as a possible solution to improve show pressure ?