Suzy,
sorry to read about your neighbour cutting your hedge. We had a similar problem, also we had the dog problem too.
They repeatedly complained about our dog, while she was in our garden.
They knocked down the last brick off the dividing wall. We eventually had to take action.
They have no right to touch your hedge, except the overhanging branches that grow into their property. They them must return the cuttings to you as they are your property.
People like this will continue to make problems, They seem to think the rules are made for you to obey but they can do as they like. I think eventually you must take a stand.
Our neighbour is currently burning smoking fuel in a smokeless area. Aparently the law is 'not to sell' the fuel. To burn it seems to be within the law. Best of luck Browtal