Steven,
This is just the sort of help i'm looking for, never mind it's in the wrong section
The points you mention especially the empty left side, are really valid and I had been struggling with them myself, in the end i gave up trying to figure it out and left the left hand side empty to see what the reaction would be.
The client saw another painting of mine and was quite definite about the pose, and the fact that he should be looking with affection at his 'toys' and no ref to the fact that he is a minister as that is not how she sees him. A bit of background info., the trains are in the garden with an enormous landscape with track, signals, waterfalls, cows in the fields etc etc.
Initially I had another train engine in the bottom left to give some perspective and balance the comp. but this only made the painting look more like a painting of trains and a man not the other way round (which he was really happy about

)
Another idea was to add a couple of train signals especially the one shaped like an arrow and have it pointing upwards towards his face. These would be only sketchy additions as the bottom of the painting, fading out and losing colour ( as in the painting she first saw).
This is really useful as I always start at the top and work my way down anyway so I haven't yet reached the part that could be altered.
I see what you mean about the shadow on the arm, I'll definitely address that as I reach that part of the painting.
Thank you again for taking the time to give such detailed help
Carolyn.