I can totally sympathise with your situation,i lived next door to a neglected dog,he never went on walks,he never got to go inside,the family tossed scraps outside for food,he had no shelter,it gets up to 43celsius here in summer!!!This poor little dog sat outside and cried day in day out!i ended up walking him everyday and feeding him,so in essence i was looking after 3 dogs,i have 2,I dont know what it's like in the U.K but here in Australia the Italians dont beleive in vets and dogs are third class citizens who are only good for being watchdogs!My neighbours are italians,i dont mean to be racist it is just a common pattern with them!
To cut a long story short,i called up the animal welfare(not r.s.p.c.a they are the same as yours here!!!) and asked their advice,we came to the conclusion that this dog was better off away from these people and they had a very long waiting list of people who wanted small dogs,she never told me to steal him but indirectly hinted ;) So one day when they were at work i sneaked over and took him,i then took him the animal welfare and the rest is history,he is now with a wonderful family who lets him sleep on their bed and who love him to bits,now he will get to live out the rest of his years a totally pampered pooch :D he was 4. I have never once regretted my decision,this dog would have been better off dead than living with these horrible people,they never even came over to ask me if i had seen him

If faced with the same dilemma again i wouldnt hesitate in doing the same thing,i will NOT stand by and watch an animal be neglected or abused,the worry would just consume me as the above dog did,in the end he was all i was thinking about!I could not live with myself if i knew this was happening and did nothing about it,forget the r.s.p.c.a and get some strong arms in to take the dogs away??I wish i lived over there as i know a few people i could send to you who could make this problem go away ;) and give those poor dogs a life!that they so deserve.
christine