It is so cold that my olive oil in the kitchen turned solid. Time to make a list.

Let's tackle the problem head on. Make a list. I really love my old timer sash windows. they were one of the reasons why I fell in love with this house. I really took good care of them, found a nice team that refurbished them and also draught-proofed them. But If I want to have it warm they have to go.
My conservatory has only a plastic roof. It is as cold in there as it is outside. Which would not be too bad, but the conservatory is connected to my kitchen. Ever experienced hard olive oil? That's what happens in the winter.
My house is an end of terrace house. And to be honest, close neighbours (they are lovely) on one side are just enough for me even though their snuggling up makes your house warmer.
Because I am replacing the windows I can just as well start with internal insulation. The walls have to be redone anyway. What about a new entrance door? Well, this can wait.