Thanks @ShaunCorbs ... I've already had the smart meter replaced as Thames Water originally thought that I may have been spurred with my neighbour so that's now been ruled out. Thames Water are saying that there must be a leak between the street and the stopcock under the kitchen sink but I'm not convinced. Can you post the URL here please as I'm getting "page not found". Thanks for taking the time to try and help me resolve this - it's hugely appreciated. Happy New Year!So it’s not internal so either leak externally or someone else it tapped into your supply
Leak seaker required
Might be worth contacting someone like This