The mystery is solved. The horse code on the underside of the base is BNH10. A British horse and indeed the horse used to mount Wellington.
So my Napoleon is riding Copenhagen. Perhaps the previous owner modelled this on an alternative history and instead of Napoleon losing Waterloo where his horse, Marengo was captured, he wins and captures Wellingtons horse Copenhagen.
A classic Napoleonic pose shows the horse furniture in detail.
Another image shows more ornate horse furniture.
Anyway I will strip both the horse and paint as Marengo. A FNH10 horse may turn up in which case I could always remount Le Tondu