I'm still focusing on the controls and have now got what I'm pretty sure is the full range of motion back in the elevator run. The stick now moves more smoothly too! Unfortunately I've been unable to move the aileron input on either side and there's quite a difference in the angle of the forks that attach to the torque tubes, leading me to believe that the two aileron controls are currently disconnected. I need to get access to investigate the circled components in the attached diagram to check it out properly. I've applied yet more penetrating oil and will investigate more next week but I'm also considering applying some (carefully controlled!) heat to try and free up some movement.
The rudder pedals are also stubbornly refusing to move despite a long soak and regular spraying of penetrating oil. I did make a start on further disassembly, but have to work methodically and have limited time at the moment.
Background research continues, I'm still considering various wheel/trailer solutions and I'm talking to a few folk with a view to stripping and refinishing the cockpit. I have a couple of new parts due to arrive this week so I can continue on working on the instruments and sim hardware at home.