Thanks for all your replies, which really are helpful. The last thing I want is to look like a spiteful neighbour who wants the dog taken away because of the noise, but if it was just the noise, I would talk to the local env health dept rather than the RSPCA. Blackcat, in answer to your question, I don't believe he has any sort of disability (although who knows?), he's just "odd" as in being rather socially inept. For example, when he first moved in, he informed me on his very first day that his dog was aggressive and that I'd be better keeping all my cats indoors from now on, and seemed genuinely surprised that I didn't take kindly to being told what to do!! He now doesn't speak to me at all and told another neighbour he finds it difficult to talk to "young women" and that he finds me "intimidating"!!! He does hold down a full-time job, but I don't think he'd have the money for a dog walking service as he's a housing association shared ownership scheme member and has a D-reg banger, and has garden furniture instead of a sofa, so I get the impression money is tight!
Your point about the conditions inside the house is a good one - as a cat owner with a litter tray, it hadn't occurred to me, stupidly!! Let's just say the smell of the back garden isn't too appealing so the inside is probably bogging ... no wonder the man is single.
Yep, I think my mind is made up. All of us in the street are worried that the dog will attack someone and will be destroyed, and it would be devastating as it is a beautiful dog that has fallen into the wrong owner's hands through no fault of its own. She is only about 2 years old so surely there's still hope for her in the right home.