The French'd also have the home advantage, they can relatively easy retreat back to their ports, they're guarded by fortresses, etc. so a breakout can't be too problematic,
That's not really practical at all. To do what the OP wants, they would have to venture further than hugging their own coast. Any further out and it's just them vs the qualitative superior English navy. The English were so overconfident on their fleet that a lot of their ships were allocated towards the Mediterranean, so if Napoleon won at Trafalgar, the British could just summon a fleet tree times larger from Malta. And post Trafalgar, which is what the OP is talking about, the French have no trained seamen. Sure they can train in harbor, but that's it. you said training isn't everything, but the British are also better on combat experience and ship design, both for First-rates and frigates,
What if he builds a really big cannon instead of the navy and fires that at Britain?
30 years later this might be possible, although 140 years later (Nazsis) shows that practicality might be a problem. It's so funny I'd like to see it.
To the OP, well between 1688 and 1940 the British always asked those who wanted to invade the Isles "Well you and what navy?" when faced with an invasion.
Nice cuttoff dates. If you said "since the Tudors" I would have pointed out the Spanish Armada heavily outgunned the rag-tag English navy at that time.
The Navy was pretty successful an interdicting and cutting off attempts at invasion, even Bonnie Prince Charlie only got through because he didn't bring all that many men with him since he intended to raise a Jacobite Army in Britain itself.
The Old Pretender might have had a better shot. At the time, a lot of the naval crews were indifferent about the whole Hannover Stuart thing. A plurality of Scottish Protestants (logic bomb) actually welcomed the idea. The 15 caught the government flat footed and were one battle away from having no Hannvoeran-British forces between them and London.
I'm NOT saying Jacobites outnumbered Georgites. In the eyes of the English as a whole, he's a filthy Catholic, not to be let on the throne. While the Jacobites had both Catholic supporters (duh) and Protestant ones (in Lancaster, Scotland, and Cornwall... the logic bomb of a Catholic leading the Church of England never seemed to occur to these people who clearly didn't think this through), the British were a protastant majority and as a whole didn't want him. Taking Scotland would be possible. England was only possible because the government forces were off foot, it was not possible due to popular support or anything like that.
Realistically the French Navy would not have been able to train without some kind of harassment from the RN, which meant that their effectiveness was slowly retarded over time. So even at great odds the RN would probably still come out on top in a pitched fight.
This is why they avoided a pitched fight over the decades. Yorktown only happened because a unit that could have demolished the French navy was repairing storm damage and didn't know Cornwallis needed evacuation ASAP not "eh... anytime next month"