Half choke martingale collar

[Tav1]

Hi brucie has been pulling for months I've tried all sorts of stuff harnesses were the worst because it seemed to encourage him to pull more, anyway I went the a show in buith Wells and I was talking to the bulldog people and they advised me to get the half choke martingale collar,so one of the guys on the stall made one for me, he still pulls. What do the rest of the bulldog use?