Dear Most Excellent Sir, Just a fan and lover of riddles here, I'm afraid... I think you started yourself a bit of a headache with the mysterious (and doubtless not terribly significant to you or your storytelling) personage of Sharpe's father, and I apologize for adding to it, but I was just wondering if Daniel Hagman might not be the gentleman in question? He might be old enough, and as a commoner, soldier, and former poacher, who survives your series until Waterloo, would qualify within some over-rarified atmospheres as a-happily-"worthless rogue". Further, his name contains the letters N.A.G., another word for a horse, as well as the additional letters M.E., which not only fits, but seems likely only to grow more apt. The remaining letters spell out a name. Perhaps it is that the original inquirer happened to be one Hilda. Perhaps not. I really need no confirmation, denial, or any answer--right or wrong (as I grow older, I find mysteries often possess more value and delight than truths--facts are of perhaps a different color, but yours is a work of fine historical fiction.). I only wanted to share this rather pleasant opinion with it's originator, in part due to your estimable character Daniel reminding me in various ways of my own beloved father (whom I'm fortunate enough to not only know fairly well, but to be quite close to). Apologies again for selfishly taking up any of your time, wonderful sir, and many delighted thanks for your very excellent works!
Jonathan
A nice try. Wrong, but nice!