Here in the states there is a method called "drift fencing", which is done by using plastic or wire fencing like "wings" funneling the animal toward the trap door. This is done on both sides of a two door trap or just on one side if the cage trap only has one door or entry. It is somewhat effective in trapping urban foxes.
Bait and/or lure, of course would go into the cage trap.
I have only caught pup foxes in cage traps and one adult.
My method of snaring and using footholds are what I mostly rely on, but not legal everywhere, I understand.
