Whilst we were on holiday our neighbours took down the fence between our two properties and have built a full height wall as part of their conservatory which they have also put up themselves. The wall which is now their inside wall of the conservatory is 6” over onto our property. Is this a Party Wall matter?
If the new wall is encroaching the boundary without your consent then it is a trespass. You should formally request that your neighbours abate their trespass by removing the wall – if they refuse your only option would be to issue legal proceedings.