Longtime lurker here. I'm wanting some advice on a house we're buying. 1960s split level bungalow, 2 bedrooms downstairs (1 in the old dining room) and 2 upstairs. 2 reception rooms and a kitchen downstairs and family bathroom upstairs. We'd like to knock the kitchen through into the dining room and fit a bedroom uostairs, maybe by adding a large dormer into the roof. House needs new windows and insulation also. It's 196 square metres. Any ballpark figures for this? Thanks in advance. x