Rejigged left front armrest and it now fits over torque tube. Graft a 5mm fillet on the bottom to make up the lost geometry. Graft in a new central transition bit of 3/4" H45 with urethane bond, remove the extra bits I added last time and jig the map pocket edge straight with a block of wood and leave to cure in place.
1 x BID for interior of left front armrest access door, and fixed part of left rear armrest
Tape up a block of urethane and hot glue it to the fuselage side to make a flange to mount the removable rear armrest to, similar to the main landing gear cover flange suggested by Wayne Hicks, avoiding the need to drill anywhere near the fuel tanks. 4 x BID from this to the fuselage side.