If, as you say, they come tearing out of the gate and onto the public highway, you should gather as much evidence as possible (times, dates, witnesses, photo's etc) and let your local council prosecute them.
Not many people innocently walk around with a lump of wood so I think you're on a loser with that one should the police become involved.
However, if you happened to be carrying something else which could be construed as an innocent object, and you had to use it to defend yourself I think you'd be OK.