Rob
I get the impression that it wasn't easy to progress a military career after being commissioned from the ranks - though I note that some of the 5/60th certainly did. Fothergill was clearly a smart fellow, rising from drummer to Sgt Major in ten years and then utilising his admins skill as adjutant for both the 88th and 39th regiments. His next, and last, promotion was to an unfashionable regiment - 98th - in a backwater theatre - Maine, USA. Eventual retirement on half a Lt's pay would not have kept him in a grand style I suspect.
Ian