I have no idea about the law in the UK, but it seems that you have had your rights violated. I would take any pictures you have of your dogs, shot records, everything you have about your dogs to the police in person with people that are witnesses to the attacks, along with texts sent to you and stay there until they did something! Being this uncaring in a volatile situation is beyond the police being wrong.
It's neglecting to protect you- a citizen of the UK- that they are (hopefully) supposed to be protecting!