It's fine: Wide road, good sight-lines, not steep, nothing slippery. Even on a Brompton there wouldn't be any drama.
Again, the descent after Turners Hill is more of an issue, as there's some twisty stuff and it'll be dark. People will be taking it slowly. No idea what the current pothole situation is (it's ages since I've done the Brighton ride), but historically there have been a couple of nasty ones.
Anyway, given that my Achilles rebelled after King's Lynn (literally, the pain kicked in when I got off the train at Mordor Central), I'm pulling out of this in order to save it for next week's silly bike racing. Something about riding at other people's pace seems to exacerbate it, and standing around doesn't help. Have a good ride everyone!