I plan to add insulation to the ceiling of the living room its the most occupied.
Going to take down the current plasterboard and put up 30-40mm insulated plasterboard.
Might even put some between the joists as well.
If there is a way to use the thin celotex and normal plasterboard it'll be significantly cheaper!
We're buying a house so my first personal energy bill in 10 years is gonna be on new tariffs, that'll sting