At the risk of arguing pedantics
Our local law states;
A person must not cause, encourage or permit a dog to attack or worry another person or an animal.
The definition of attack is also stated in the law;
"the act of an animal holding any part of a person, animal, or thing in it's mouth whether or not the holding is accompanied by shaking, pulling, or pushing and whether or not such person, animal or thing suffers any injury.
So technically you are encouraging and permitting your dog to attack a person.
I wonder what your clubs PLI provider has to say about it?