@MooN........what I can't get my head around is why a bunch of French guys want to tour Britain?
You could go down to the Pyrenees and northern Spain, or across into Bavaria, or even up to somewhere like Denmark. And all in the Schengen area.
Plus you may not be covered with your EU health card, you may need to get a visa, and your free mobile roaming will be gone.
Also, the weather in Britain is bound to be shit, traffic backed up everywhere, and generally not particularly attractive as a holiday destination.