I Blame Communism
Banned
wasn't the American War of Independence pretty much the elites of a peripheral territory tossing out the instruments of control by the Center? as in, it was just the local Old Order replacing the national one.
Anyway, a England similar to post Napoleonic France would be interesting. However I'm pretty sure that at that point the Commons had enough institutional clout and smart politicians in it that if the "Nicholas" analogue pushed to hard they'd probably set themselves up as the opposition, or push back via the means that the law allows. That is, letting the King try and govern without income.
Anyway, if you want a revolution you could have (VERY loosely):
1.Commons attempts to pass GRA equivalent
2.Lords block it with support of the Crown
3.rioting across the Isles, probably an organized run on the banks, and Commons block any more income to the crown
4. At this point the result depends on (assuming that the Monarch is willing to go for broke and won't accept any of the compromises that Grey or his equivalent is probably frantically suggesting) the loyalties of the army. If they support the Commons then the Monarch "voluntarily abdicates" and the GRA passes.
However if the army's loyalty is behind the King, then Parliament is prorogued, and the Reformers are arrested.
The King can then either try and get a sham election to bring in a Commons stuffed with Tory's, or rule through the Lords. Either way, the government lacks any legitimacy in the eyes of the populace, the economy is a complete wreck, and the major urban centers will have to kept in a state of more or less military occupation to prevent any riots or protests. I think its obvious how things can get out of hand from here.
Interesting stuff. Paris, 1830, is a very interesting example to look at: the king's plans to reshape the country on reactionary lines run up against a lower chamber which refuses to pass them, he tries to get round this by subterfuges and finally alter the franchise with the help of the army. Educated radicals in the capital engage in mass pamphleteering and economic sabotage, the destitute mob get their hands on guns, and once the authority of the state in its capital has thoroughly ceased to exist, senior liberal politicians step in with a fait-accompli.
In France, of course, it led to a new monarchy as favoured by the senior liberal moderates (the Greys, is you will), but in this alternate Britain there's no obvious alternative like the Duke of Orleans, and of course the monarchy, having gone through three German Georgies and now this "Nicholas", may look a bit of a spent force...