...I had a situation where the threat of a slave rebellion supported by Wellington's Peninsular Army was used to halt the 1812 war in my Greater London to 1813 ASB.
https://www.alternatehistory.com/discussion/showthread.php?t=289822
Any successful revolt has outside support whilst the government is distracted by greater concerns. E.g. the rebellious colonists in 1776 and the Irish Free State under De Valera (So I'm pro-Irish, so what? Although I'd prefer Michael Collins - and the Dominion of Ireland).
I'm pro Irish too and I still think de Valera was an ass.