Two duels...
DUEL
A meeting took place yesterday on Wandsworth Common, between Lieut.-Colonel Sir Robert Gill, Lieutenant of the King's Yeomen Guard, and D. Finlaison, Esq., in consequence of a very serious dispute which occurred between those Gentlemen at one of the Clubs.
The parties were accompanied to the ground by Sir J. Wedderburn, Bart., and Lieutenant Walsh, Royal Artillery; and after receiving Mr. Finlaison's fire without effect, ?? Robert Gill fired in the air, when an explanation took place satisfactory to the seconds, and the parties after becoming reconciled left the field.
Mike Tuffrey writes in response:
[I am] curious about the identity of Sir J. Wedderburn, Bart, one of the seconds in your dueling stories - I recently got lost for several months down a rabbit hole, more a warren actually, around the Websters and Wedderburns of Clapham Common (not helped by their habit of changing names to secure inheritances)...
Certainly it's not this one:
Wikipedia: Sir John Wedderburn, 5th Baronet of Blackness
as he was hung drawn and quartered on Kennington Common a hundred years earlier having picked the losing side at the Battle of Culloden, the consequences of which trickled down the generations and overseas including the ever present enslavement issue, the ill gotten gains turning up in grand houses around the Common.
Nor, as I first assumed given the Wandsworth link, his nephew John Wedderburn who lived next door to Wilberforce and Henry Thornton 'between the Commons'. He died in 1821 and anyway didn't inherit the baronet title (as far as I know).
His sons were James and John, but neither were knighted (I think) and only one was alive in Dec 1831 (James).
So I'm assuming it is James Webster Wedderburn (1788-1840), who was knighted (a great nephew of Kennington man - and all the more ironic for a Jacobite descendant that he got his knighthood from a Georgian king)
Wikipedia: James Webster-Wedderburn
In theory he was known as James Webster Wedderburn Webster (father's name changed after his birth) but he doesn't seem to have used it, Wedderburn being posher. He was a right old cad and duelling would have been his thing (boxing definitely was). He cheated on his wife, gambled the fortune away and then embroiled the rest of the family in a fruitless court case before dying (of drink?) in Dublin. He was born in Clapham, one of our less savoury characters.
Feels like him, but doubt we could prove it.
The only other possibility is Sir John Wedderburn (1789-1862), grandson of the Kennington Common man but with no obvious Clapham or Wandsworth connections and altogether more sober and serious. This about his father:
Wikipedia: John Wedderburn of Ballindean
And this about him:
UCL: Sir John Wedderburn
However he was supposed to be out in India at the time, not returning home until 1837.
All of which is rather inconclusive and needs to come with a severe health warning about Wedderburn-shaped rabbit holes...