Just an update,
I just went down to feed and ready for a war. My weapon: a dressage whip. Tess was an angel as usual and stood patiently for her feed. All good. Now Lucy is straight up to the gate and crowding before I even get in there. A hard crack on the fence with the dressage whip and she went flying across the paddock. She didn't come near me again. Gave Tess her feed, Tess waited to be invited to eat. All good. Went to give Lucy her feed and she invaded me before she was invited. She got chased away with the whip, swung Round and lashed out. Well she got a hard crack across the rump (or wherever it connected) with the whip. She gave in and waited until I invited her. Got the message now she does. I'm not letting my guard down though!
P.S. Whacked my arm hard on the tree coming out and now my arm is VERY swollen and sore, just wont show mum ;)