The end of my dad's garden backs onto a number of paddocks which have 4 horses in them belonging to the same person. We haven't seen anyone around for ages now and the horses have started eating the fence posts; proper bite-sized chunks taken out of them. They have no hay and there's no grass, just mud. The horses are clearly not in a good way. 
My dad's clearner, who has horses too, has also been concerned about them and yesterday, between them they decided to phone the RSPCA to get them to come out and do something. Apparently the horses didn't even have the energy to eat the carrots the cleaner tried to feed them.
So after 2 calls yesterday and another today, they still haven't come out. My dad also called the Hampshire police who said they'd refer it onto the local police, but they've done nothing either. He wants to go and get some hay for them to eat, but says it's better for the police to see how they've been left as it will help them prosecute the owners (my dad's ex-police so I guess he has his police head on). So in the meantime, these poor horses are wasting away.
Any advice on what to do next? I can't believe the RSPCA have been happy for these horses to starve for another 24 hrs since they were notified and are continuing to do so. 