Dear Bernard. In 1826 Wellington was sent to Russia on a mission (essentially to prevent another War) and it was after the Decemberist Uprising. I wondered of you were tempted to send Sharpe along with him. Sharpe in Russia would be fascinating.
Regards
Geraint
P.s I saw this article on the subject you might like https://adventuresinhistoryland.com/2014/03/17/the-duke-and-the-tsar-part-1/