I know this boiler is a re-branded halstead but not 100% sure what model. Basically I've had someone call me about replacing the diaphragm, someone else has already diagnosed this as the problem for intermitent hot water fault. They quoted about £200 to replace it though, which for a £30-40 part is excessive. I've been asked to do it, just wondering if anyone has changed one before and how easy it is? I've had nothing but bad experiences with Halstead boilers before so I am a little bit dubious about taking it on.