I will try the first bit of that video as that looks helpful
the 'lets go' and turning away we already do to varying success.
He was goodish on his walk tonight, I kept him distracted from some of the larger dogs and although he kept looking back he did keep walking when some behind us were barking. He even kept walking when there was a dog a little way off behind us although again he did keep looking back before catching me up (he was on an extendy lead and halti) The problem was when a terrier was coming towards us and we couldn't turn back. I tried something new...I got him to sit and treated him for sitting patiently and all was fine until the terrier actually passed us and then he started to lunge and jump about to try and get free of my grip...he scared the hell out of the girl walking the terrier! I had to pull him away as soon as I could. It was worth a shot