small door trim

[Zaffy]

There is a small door in a bedroom wall to allow access into the eaves/roof.
It is ill fitting and draughty. The gap between the door and frame on the wall is a few mms on all sides.
I have removed the hinges and put magnets on the door and inside the frame so it holds securely in the hole. I want to pin/glue a wood trim on the door slightly larger to cover the gaps.
The frame in the wall is not exactly square. Should I cut the frame mitres at 45 degrees and then pin/glue onto the door overhanging a few mms then rub down the overhanging trim to make it fit the hole in the wall?

 

[Woodchips2]

If you've removed the hinges and relied on magnets why not pin and glue a piece of architrave on the face of the door so it covers the gaps completely. These could be mitred at the corners and it wouldn't matter if the frame was out of square.

Regards Keith