After gently bending the access door several to get its curvature to more precisely conform to that of the cooker main section, I found that I still has a gap at the top of the door because it would fall outward from the main section. A close inspection of the rotatable tab attached to the knob revealed that the free end of the tab was too far away from the inner wall of the main section to make contact when the knob was in it door latching postion. Two gentle taps on the free end of the tab with a hammer bent the tab in a bit and solved the problem. Now the top of the door is snug againt the exterior wall.
John
John