Hi guys, Need a little help here and very new to all of this. We have a Victorian house and are struggling with low water flow, although pressure is ok. We want to have a decent thermostatic shower. Currently it is on a common supply pipe and we are house number 5 and it has a combi boiler. The (hopeful) solution we settled on was a new water supply pipe. A new 25mm MDPE pipe has been put in and is going to be connected to the water main. We thought it would be best to feed the new water supply into the boiler to deliver it the greatest flow rate. The plumber came this morning to fit the internal stop tap and make the connection into the house system. He has connected the 25mm supply pipe onto a 15mm copper pipe, which then runs to a T junction and splits into 2 x 15mm pipes, one which supplies the boiler and the other which supplies the rest of the house cold. Given that we want maximum water flow to the boiler and also to stop the problem with flushing toilets/taps/washing machine at the same time, should he have run 22mm pipe up to the T junction? Have attached a photo. Any advice greatly appreciated.