Hi Dave Things slowed up a bit because of overrun on the kitchen installation. However, I have decided to have the megaflo installed. I have just last week had two G3 registered (certified unvented installers, one a BSc grad!) plumbers quote me for the job. They had both said it would be no problem given the pressure and flow rate I have, which is about the same as yours I believe, although all the mains pipe inside my property is now 22mm. One of them suggested that changing the lead from the mains to the property with a 32mm pipe would increase the flow rate by nearly twice!! I'm afraid I'm not convinced until I see it but I'd be surprised if it didn't improve substantially - Thames Water wouldn't commit to any improvement (afraid that you would hold them to it) but a Thames engineer who visited indicated that it would saying that people who change the lead mains do it to increase flow rate. I have also had people quote for replacing the lead so I think I'll have the megaflo installed and if the performance is not up to standard then I will always have the option of replacing the lead. The cost of replacing the lead is varied. There are two parts to this - one is the run from the property to the stop valve, in my case in the sidewalk just outside the front gate, two, the communication pipe (chances are it's also lead) from the stop valve to the mains. Basically the householder's responsibility is within his property bounds and the rest, the communications pipe, is the water authority's (Thames) and only they can do that work. But Thames have a list of approved groundworkers who can self certify and do the work till the stop valve. But the rest has to be carried out by Thames as it involves digging up the road. Sorry, rather a long post but hopefully saves you a little time if you decide on the lead replacement. I hot linked to your post from my inbox message so I don't know which topic you posted to but I appreciate your post and if you wish to exchange views, that's fine.