I've spoken to the man of the house tonight and we think we have come up with something. I've now got some plastic material, like webbing, and I'm going to attach it to the fence so that the dogs can't see one another. We'll know in the next few days if it works ;) Heide only barks when she sees my dogs, and mine retaliate now :( It's such a shame, as their last GSD was so friendly with my dogs that they are a bit confused with this new one. Heide is immediately recalled when she starts, and is quite good at that, but I really don't want the pups frightened.
My dogs are never given free access to the garden any more after a different neighbour complained when a pup from my last litter (aged 13 weeks

;) ) growled at them when he saw them in the garden for the first time. They didn't complain to me, but to the local authority :( I'm always out with them, just in case. I've actually seen their son throwing stones at my dogs in the past :(