How?
The iffy bit here plausibility-wise is that the RN wouldn't be there in the first place (never happened in OTL across a century of French invasion attempts), not that it could be permanently knocked out.
Yea, but my issue is that I can't see a lightning French descent upon, say, London, and then a capitulation flight. The French will need reinforcements and supplies, and unless the French defeat the British fleet that returns, they've lost thousands of men in the descent on England.
IMO.
I doubt they could pull that off. The Hanoverians weren't super-popular but Charles would most probably have dissolved parliament and tried to rule directly, using his supporters from Scotland and Ireland and his French mates to hold down the country.
Hrmm, you think he'd bother to dissolve Parliament? There were still some Tories around...
I wonder how far, if it at all, this world would be behind ours.