I will first descibe everything I can about the situation (essentially: one animal attacks another). We had just washed my dog (A boxer/mastif cross) in our back garden and so he was off leash as to not get his collar rusty and such. Unaware that the neibours dogs (Staffodshire Terriors) were being let outside while we were out still we let him stay off leash for 5 or so minutes with someone out to watch him. While at the fence line the neibours dogs began to aggress our dog at which point our dog reacted. The fence is a short chickenwire type fence and our dog easily leaned over and bit into the back on the other dogs neck. after about 10 secconds we seperated the dogs and no major injuries happened (some small punctures on their dog at worst). After this their owner continious to yell abuse at both me and my mother saying how he will come over the fence and attack me and such and generally spouting vile language at us. Now, his dogs are highly agressive to both people and dogs and often are at the fence growling and barking and so on. Quoting what he told us when we moved in (Dont reach your hand past the fence ever our dogs will take your hand off) and such. Yet he knowingly leaves his dogs out in the yard off leash and unattended most of the time most days. For that reason when we let our dog out into the gardern we keep him on a long leash. As stated before he wasnt this time because we were bathing him. Now, he threatened all kinds of things from large vet bills, having our dog removed or put down, and so on. My legal question is does he have a leg to stand on? He knowing has agressive dogs free roaming his garden off leash and a very poor quality fence. We always have ours tied up and only had him untied for cleaning and at what point his dogs were inside anyway. I feel like simply because our dog was the one that one would say came out better in the fight he deems us in the wrong.