Im also fairly sure that there is a law that if you cannot control your dog off the lead 110% of the time they can complain to the council/pound/whatever and action be taken against you, i cant remember what action exactly but any action against you is unlikely to be a good thing.

My dog....funilly enough called Daisy is a 1year old lab and is SHOCKING at recall. IN the garden off the lead she'll come just from you clicking your fingers, everytime. Outside she'll come is she is on a flexi lead and you have a treat in your hand. If we are out in a field and she is off the lead and you call her, she will run up to you untill about 6ft, smell both your hands and then leg it if there are no treats present.

The other day we were lucky enough to have her on the lead when another owner let their dog off in the same field. Daisy was going mental, whining, spinning round in circles....cant imagine why we werent letting her go. We waited for the dog to leave and then waited another 5-10mins. As soon as we let that lead off of her she was gone straight down the other side to where the dog was, we called, we whistled everything, she ignored totally. Even when we walked down to her and were shouting "naughty girl" at her in the gruffest voice, she didnt even bother looking up....nihgtmare

Anyway, Daisy doesnt go off the lead now, its not worth the hassle, law suit or vets bills her inconsistent recall will cost us. With your issue however, try shouting her name and then running (stamping your feet) in the opposite direction. This used to work quite well for Daisy untill she figured out what was going on. Be prepared to grab the collor at high speeds though.