Post-apocalyptic Britain, character known as "Hat the Boat"

Question

I'm not sure about any of the following.

Book set in a post-apocalyptic Britain, the title may have had "Worm" in it.

There was a character who was just known as "Hat", or sometimes "Hat the Boat", because he had a boat and ferried people up and down a river (might have been the Thames).

There's a boy who has epilepsy and sees visions, which he thinks might be prophecies, possibly they were. He breaks into some mysterious pre-apocalypse ruins, thinking he might find something there that will explain his visions. It turns out that it's an old Air Force base and that there are people living there who still have some old technology.

There's a woman whose father or husband is violent, or possibly both in succession, and she runs away and ends up becoming quite powerful in the area and some people think she's a witch. This is a sort of flashback sequence and takes place before the bit with the boy.

The boy ends up with a group of people who have some pre-apocalypse weapons and are planning to take over and rule the country, possibly the Air Force base people from earlier. They get into a stand-off with another armed group led by a woman, possibly the "witch" from earlier, who have some pre-apocalypse drones and can use them to spy on people, giving them an advantage.

The book might have been a collaboration in some way, or part of a series that was a collaboration. It's possible that some of the things above are from two different books, I'm not sure.

Answer 1

Haven by Adam Roberts:

Young Forktongue Davy has visions; epilepsy, his Ma calls it. He's barely able to help around the family farm. But something about the lad is attracting attention: the menacing stranger who might be the angel of death himself; the women-only community at Wycombe; Daniel, sent by the mysterious Guz. They all want Davy for their own reasons. But what use can he be to anyone? He has visions of flight, but how can flight ever be possible in this shattered world? A simple farmboy, caught up in events beyond his power to control-but his visions may be the key to the future.

It is part of the Aftermath series, though that appears to have stalled at only two books.

The reference to Hat the Boat is:

They called him Hat because he always wore a hat. Sometimes they called him Hat the Boat, because he had a boat. They didn’t call him anything else, because, frankly, they didn’t often have occasion to talk to him, or about him. He kept himself to himself, and rarely walked the land, and he was happy with that, and doubtless they were happy about that too, or would have been happy if it ever crossed their minds.