Thank you Julian and Clive, you both make a very valid point.
At present I can reach both injector valves and regulator on my loco' and fire on the run as well – on a raised track. We regularly run for the public for 3 hours at a time, but by the time you finish the back knows about it!!
However I also run ground level, not hauling passengers, which necessitates a different sitting position with my backside at the front of my ground level driving truck and feet on rests sticking out of the tender frames. Not possessing arms the length of a Oranutan does require more bending of the body which fortunately I can still do but if I can make it easier then I'm going to at least give it a go. I can always revert back if necessary.
Some ground level drivers sit on the tenders of their loco's but being just over 6 feet if I did likewise I'm not sure driving with my knees up around my ears when bending forward is going to help my physical wellbeing.
Regards.
Chuffer