This Article on the 1808 Russo Swedish War will be of interest to read. Given that the Royal Navy and a British Army under Sir John Moore ended up there. I wondered of you were tempted to get Sharpe there. There would be time before the Peninsular War but after Sharpe Prey. The Swedish King does sound absolutely mad and the Swedish and Finnish Troops seemed to out fight and beat the Russians a lot but tragically for them were let down by a terrible High Command Regards https://www.napoleon-series.org/military-info/battles/c_finnish.html
P.S Please please consider a book on the War of 1812. I know I'm not the only Fan, British or American of yours to want that. Even if you're reluctant to use Sharpe you could always use Frederickson or Chase instead. The Glengarry Light Infantry were nicknamed the Black Stumps and operated in the 95th Role in Canada and in a lot of fights
I fear I’m not tempted – I gave him one foray to Denmark and that is probably enough!
I’ve been tempted by the War of 1812, but there’s no gap in the chronology that would allow Sharpe to cross the Atlantic – but I’ve done a huge amount of research so may yield to the temptation with another character?