USA Unvented cylinder - water pressure

[Tim0212]

Hi, looking for advice about unvented cylinder. I had one installed as part of a horrific modular loft conversion that was recently finished. The water pressure in the bathrooms is poor, probably worse than when just had combi and I cant use two showers/bathrooms at one time which was the point in having it installed. When first installed it seemed good but then there was a leak in the system. Leak was fixed but pressure now poor. The tested cold incoming measures at 22 lpm and 3 bar but when i check this in bathrooms its less than 8lpm. The plumber is refusing to return as loft company arent paying him(think theyre going under) and his only advice is that the incoming supply is the issue. Im not convinced though due to rate during test and i've recently tested outside tap and its 3 times quicker than inside. The new shower in loft occassionally has fluntuating pressure that you can see by eye. Does anyone have any advice?

 

[Mark K]

Yeah its a dark space. Hopefully these help

View attachment 35438

View attachment 35439

Is that pic the right way up? the pump is on the ceiling with the head pointing down?