Boilers have never been allowed to discharge across a boundary, more so if the wall is the boundary as the terminal is effectively in neighbours property. The neighbour would have had every right to request you move boiler as he wished to use wall.
OK granted he shouldn't have touched the flue and is being silly expecting payment.
For the sake of yours parents and the peace I'd let it drop, if the neighbour is still asking for money? If so tactfully explain that what he did was naughty and you'll drop it if they drop the money.
The issue with flue/boundary is more of an issue due to condense, the rules have always been there just never as stringently adhered to.
OK granted he shouldn't have touched the flue and is being silly expecting payment.
For the sake of yours parents and the peace I'd let it drop, if the neighbour is still asking for money? If so tactfully explain that what he did was naughty and you'll drop it if they drop the money.
The issue with flue/boundary is more of an issue due to condense, the rules have always been there just never as stringently adhered to.
