Hi Richard
I agree with all that has been said, each element of your piece is superbly made and finished but, to split hairs with my jaundiced eye, they don't seem to complement each other as well as they might.
May I suggest you take the picture of the whole piece and, first of all, cover the finial with a finger. Has that improved the piece at all? I believe it does.
Now cover just the top half of the finial. Has that improved the proportions at all? Again I believe it does.
If you agree, and there is no rule that says you should, then I believe a either a shorter, and perhaps a little lighter finial would bring the overall proportions closer to the famous thirds rule. An alternative route to the same destination might be to stretch the stem but now that the glue is dry that's out of the question.
To try my theory you could knock up another, tempory, lid/finial combo to the new proportions and see what happens.
Hope thats of some help
All the best
Brian
PS I'm still not totally convinced I could have done better........