I’m going by what they’ve used on the adjacent door which is 45mm wide architraves, plus the 5mm from the edge of the frame so I’ll leave a 50mm gap around the frame. I asked the owner of the house and she didn’t have a clue so I told her what I was doing and she said that’s fine.I would find out both. The more information the better so you can get your bit right from the start it's those finishing bits around doors etc that make or break the finish of a job