I am Planning to Remove a Chimney Breast in my Share of Freehold Property. Who do I Serve Notice on?

Question

I live in a converted house with a ground floor flat (which I own) and 1st floor flat (owned by my neighbour). We both own a share of the freehold. I would like to remove a chimney breast inside of my flat which lies on the Party Wall. The house next door is also a converted house. My next door neighbours own their flats but are Leaseholders (over 80 years on their leases) and both have the same Freeholder. The ground floor flat is rented on a rolling 6 week period.
 
I have already had some conversations and served a few Party Wall notices to my neighbours. So that I perfectly understand who to serve the notices to, do I serve
 
1. my neighbour in the 1st floor flat above my flat (which I have already done)
2. my next door neighbour who is renting the ground floor flat on a rolling 6 week period AND to the owner/ leaseholder of this flat
3. my next door neighbour who lives in the 1st floor flat and the owner/ Leaseholder of this flat (which I have already done)
4. AND to the Freeholder of the property in #2 and #3

Answer

You should serve notice on the leasehold owner of the corresponding flat next door and the Freeholder of that property.

The work would not be notifiable to the owner of the upper floor flat next door (unless that property is lower than yours and you therefore share a section of the party wall), the owner of the flat above yours/your joint Freeholder although it is likely that you will require a license to consent from them (check your lease).