Horrible to be on the receiving end of such an attack. Also so very sad for the pitbull that it has ended up like that. That sits with the owner but sadly they cant PTS the owner or take their bollocks so at least they dont reproduce.
Not heard from the police since. Anyone have any experience of a similar situation or able offer advice? Thanks.
Cant comment on the police bit, other than escalate to the desk sergeant/duty inspector if no response.
Also as a long time staffy owner I can advise how to get a staffy off. No idea if works for a Pitbull. A staffys instinct is to go for a choke hold on the neck so they grab on, lock jaws, hang on and then shift their grip towards the neck. Your instinct is to try and pull them off if they have a hold, but its difficult because their jaws are locked. Its better to grab their collar and actually push them into your dog, at some point they will start to suffocate and gag for a breath. At that point pull them away. It takes a confident approach but really does work.
I learned this from having a rescue who was a scrapper. Sadly he ended his days muzzled. I will add all the 17 other staffys we have had from pups or rescues had no issues with other dogs once trained. Its 95% an owner being a dick thing.