One idea that might be good for the dog, could you offer to walk it?
Then you don't need to go to bridgend/newport to hand it over to a shelter, and you don't need to risk handing it in to the dog warden either, but it ends the excuse for the dog being out.
I know owners like that deserve things I probably shouldn't write on this forum, but the dog doesn't deserve to go to a charity shelter or risk whatever happens to unclaimed dogs the council get.
Alternatively, find someone who wants a dog, convince them he's perfect and rehome yourself