I've never dug a rabbit with one of my own dogs but I have dug them digging on in tight tubes and bollocked them for 'rabbiting'.
I did once dig 2 rats in a stop end with one. A young dog only gave a slight mark on the lead so I let him run through and got a mark at 2 ft, dug down and he was digging up a tiny tube. Pulled him out and a rats head appeared, it jumped out and was away. Then another appeared and it only made it to the edge of the dig before my mate volleyed it into kingdom come! Lol