Hey Pete,
I've had quite a bit success with it, i would definitely recommend doing it because it has helped me massively with my recovery, I haven't fully mastered it but it helps me immensely when i go out not just because it helps me to actually go but a big part of it is the mental reassurance that that I can make my self go, don't make the mistake of using it in a too stressful situation because you need to gradually build up because for me if I'm really stressed in a bathroom because I haven't desensitised enough for that particular situation the breath hold won't fully work I've found. If you have any other questions just message me