by the time you have done laying all your nets (thats if you can get in through the bramble and nettles), let the set rest, sent the ferret to work and dug out all the young rabbits, you might be lucky to get a couple of small sets done. i myself dont ferret summertime for these reasons if i can help it, but i have and i'm sure it wont be the last time.
i do prefer to leave them in peace if possible though, allthough popping a few 3/4 grown with the air rifle is good fun this time of year.
less summer ferreting = more winter sport
good luck with it if you do, and get some posts put up