Clearly this is common law nuisance and/or negligence. You need to get together a quotation for putting right everything that is wrong and tell him exactly how much you are prepared to settle for. You need to put this in writing and give him until a particular date to resolve the issue failing which you will take him to court to recoup your costs of rectification resulting on the damage.
I’m assuming that he has not paid any money yet if he has, you have not accepted it as any kind of full and final settlement
if he doesn’t pay what you are asking for and what you can justify having spent, you can take into the Small Claims Court quite easily here www.moneyclaim.gov.uk
if 3 of you do the same thing at the same time it may focus his mind that he needs to settle this matter otherwise you will have three separate sets of proceedings to deal with.
Can I clarify anything for you?
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