Doors in period houses have sometimes been removed or blocked in. You can reinstate a doorway and door.
Look at surviving doors and the Design section of Bricks & Brass to guide your choice of replacement doors. Try to match the original architrave.
Companies in our Products and Services Directory can make doors, and offer new and original brass and iron fittings.
If no doorway exists, first find a door; if you want a salvaged door, it is easier to buy a door first and tailor the doorway to match.
The carpentry required for a doorway is quite simple but if the wall is of brick or stone, you may prefer to use a professional. If the doorway still exists, look for a door which matches or is only just too large for the doorway; if you cut down a much larger door, you will weaken it and spoil the proportions.
For companies specialising in this area, see the Products and Services Directory.