Well you sucked me into the Sharpe's father riddle - so I will just make one guess and give up. My thoughts go to whomever might couple with a prostitute in 1776 (around October). So I will say John Montagu, the Earl of Sandwich. Thanks for the Sharpe series, in my opinion it is second only to Patrick O'Brien for originality and historic accuracy. I know I learned more about the Battle of Waterloo from your book than several texts on the subject.
Jerry Desmond
He should have been so lucky, sorry.