What seems likely is that the bathroom was installed with reasonable care and skill, and a few years later one of the components has failed causing loss and damage to you and your neighbour, which you are presumably covered for, and in respect of which you can now submit a claim to your insurers.
If they believe the installation was below standard, the policy might allow them to refuse payment - so blaming the plumber, without evidence, might come back to bite you.
Presumably the plumber, not you, supplied the valve.
Blup
If they believe the installation was below standard, the policy might allow them to refuse payment - so blaming the plumber, without evidence, might come back to bite you.
Presumably the plumber, not you, supplied the valve.
Blup