Hi - sounds like a really challenging thing to deal with. I would try TTouch with Stanley. It won't make things worse and it can be done in conjunction with any other things you are doing to retrain him.
Here is a link to an article about TTouch that I wrote for this site:
http://www.itsaspringthing.co.uk/TTouch.htmI would agree with Penel. Walk him in a harness if he's pulling. Dogs necks are more fragile than we realise and neck injuries can be quite hard to detect. Dogs can injure themselves pulling in harnesses but their weight is more distributed so it's less likely than on a collar.
I do have a bit of a thing about lead pulling. It isn't good for the dogs and it also isn't good for the human at the other end of the lead. Easy way to get back / shoulder injuries.
I'd always prefer that if dogs can't walk nicely on a lead that they wear a harness for walking.
Tracey xx