After 60 years the rot has set in.



Things I know -
Standard door opening.
Shorter than standard height.
Double brick constrution.
140 x 50mm frame.
I can find 140 x 45 in H3
Sash cover is twisting off the inside.
Polar door frame is too high, narrow and too wide to fit the window and be flush inside.
Lynx steel frame looks to be too narrow
What I don't know -
How it is fixed to the cavity?
If it is structual?
What I hope -
The widow is ok and I don't need to test out a polar window fitting to a polar door frame and pack the frame gap at the one side..
It looks like a swap of like for like unless someone has another bright idea?