I've read the main predators are badgers but this is unlikely in most urban gardens. I have heard foxes will sometimes prey on hedgehogs. I'm guessing, in an urban environment, foxes have plenty of food so there is little need to predate hogs.
Both visited again last night but neither appeared to be aware of the other, well the fox did not seem to be aware of the hedgehog - the hedgehog rarely seems to be aware of anything.
Recorded one locally the other evening. 1st proper "sighting" this year (though one did briefly wander past the camera a couple of days ago, jut stayed out of focus and mostly off-frame!). I guess at this time of year (plus colder temperatures last few days) food is the priority.