Anything and everything Spitfire.

Both doors on my car line up well with the bonett gap top to bottom, and front sill. They also line up well with the rear door post from door top down to where the door skin is shaped to follow the rest of the car profile. Here it begins to leave a gap until at the bottom of the door there is a gap you can just about get your finger in!! This gap decreases until about half way forwards along the door bottom the fit is ok. I have checked the sill alignment and this seems straight (straightedge wheelarch to wheelarch) as its had new sills at some time and I was wondering, as you do, if this had been done properly. Also the doors seem solid enough but I have not had the car long enough yet to have them off for a good look.
Any pointers to look for please? Thanx all
Phil