We got medieval today. Heat, pounding and jacking were involved, but the key step was tightening the tensioning nut
back up with a 3 ft pipe wrench and a 6 ft pipe extension. This actually cracked the tensioning screw loose from its spherical seat bushing and with some more heat and jacking the track off the top of a road wheel with a 20 ton jack, we got the tensioner loose enough in the seat that a quick application of right hand neutral steer would pull the tensioning screw back.
The pic below may make my description easier to understand.
Malcolm
