Just overheard the neighbours stove installation person telling my neighbour he will need to cut into the stack which I believe is shared. I have a log burner installed and obviously am happy they are getting one too

[Noelshighflyingturds]

However should I have been informed and should there be a party wall agreement in place please ?
photo enclosed

My understanding is that if you are doing any work on a shared chimney it would be subject to a party wall agreement. I came across this - when looking at getting the Chimney re-pointed. It would have made sense for the whole chimney to be re-pointed - neighbours would'nt agree and it never got done.