Used. Removed during house refurbishment. The brown one has a piece of white painted ply attached to the rear. It was common to cover up quarter panel doors in the 50s amd 60s in an attempt to make them look "modern". This can be pulled off though. I did it with a door in our house, pulled out the tacks and filled in the holes and repainted.
Measurements for door in is on the pic.
Wooden quarter panel door (Great Northern Road DE1)
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