This is a continuation of my last question about how long it would take the tunnel between the two countries to fall apart. So let's say that there's a group of people who have no more than 17th century technology; how would they get from England to France? I was originally planning for them to take the tunnel, but apparently it would fall into disrepair rather quickly. Another factor to this is that there are government forces patrolling the borders of France, so if they could be unseen that would also be helpful.
Edit: This is in the future, not the 17th century. And the reason I'm assuming they don't know about the people living in Paris (the only city left) is because water levels have risen and there are people preventing them from crossing over.
Background: I've put this in other questions, but I'll include it here as well. At some point there was a plague, and the basic backstory is that a bunch of rich people and inventors came together and created a very prosperous community in Paris. The city is heavily protected, everyone is rich, and they get their resources through mechanical means, so there is no impoverished class. Over time, people were taught that the outsiders (people who had survived) were barbarians. In reality, the city's military, which is separate from the rest of the people, prevents the outsiders from improving their technology or getting to close to the city. My characters live in England, and are some of the people who are restricted from modern technology, and for reasons not included here they find out about Paris. They are understandably curious, and try to get there. My question is how?
Edit #2: There is no nuclear waste or anything environmentally dangerous, just an army with superior weaponry preventing them from going to Paris.
If I forgot anything just ask