Dear Tim, I was not aware of anyprofessional arboricultural use of Murphy Mortagg, and the answer is simple. There isn't one. You are right it is a withdrawn product and was designed to treat aphid eggs on fruit trees, it has no effect on Horse Chestnut Leaf Miner (which has been downgraded to a cosmetic disorder, along with the leaf blight). It would not have been sprayed which is done when the tree is in full leaf as it is a Wash. Advice is merely to attempt to prevent the continuation of the life cycle of the beetle (Camerera ohridella) by collecting and disposing (burning) of all leaf material each Autumn/Winter. In respect of this I think you have a very good case of Fraud and of Negligence by Crossings. Speak soon, Liam Bullen NEUleaf