My friend was in a similar position to you,and after all polite and legal actions failed to help the dog's horrible situation,she took matters into her own hands to stop the abuse. Having already found another friend that wanted to give the dog a loving home,she and her son,got the dog out of the shed in the wee small hours,leaving the door open,like it had got out. This dog is now living a proper doggy friendly life :-). I know,it was technically illegal,but,the abuse of the dog has now been stopped.