I have a mira select shower in a cubicle right next to cylinder cupboard but the pressure is rubbish, i plan to fit a pump and surrey flange in the cylinder cupboard. Would it be ok to take two tees off the pump to another shower in another bathroom (pipes would go into the loft and back down to new shower) What pump do i need and should these pipes (from the 22mm tees to the other shower) be 22mm or would 15mm do ? Thanks in advance.