I've recently lined a bay window pier wall with Celotex, all good, made a noticeable difference. What it has also done, however, is highlight draughts through the window frame around the trim pieces, where the frame meets the walls and adjacent frames. I think it's part draught, part just plain cold - but there's definitely a breeze coming though from somewhere. It was especially noticeable last night, with the cold wind.
To try and treat this I was planning some judicious use of expanding foam beneath the trim pieces, and between the frames/wall. However, I can't get the internal trim off. There are some pics here:
Anyone any idea how these things are fitted? Is it a captive latch that clicks into place and is only capable of destructive removal?
I could go in from the outside, but the trim looks more elaborate and it'd be more difficult to repair and re-seal. I do intend to seal round it when the weather warms up a bit. This is (obviously?) where the air is coming in.