I could say I don't think there is enough regulation @VanGoSunflowers but I'm not sure its as simple as that. Experience counts for a lot but so does attitude.
My experience with dog trainers is limited and obviously we're "training" from a different perspective than with gundogs. We found puppy socialisation classes a waste of time; we tried with three of them, but it just wasn't helpful.
As regards the 1-1 training with Brie, although I have joked about Staffy man, he was by far the better trainer because he had a lot of experience. Yes, mainly focused on Bull breeds, but he still knew his stuff. He was also nicer with Brie, very warm with her, so while I don't think he was the ideal trainer for us, I think his heart is in the right place. He is a real dog person, he volunteers at a local rescue kennel, so he knows his dogs. He was the real deal and I don't doubt that he can safely handle reactive dogs.
LGD woman I found very over confident. Her LGD experience turned out to be 5 years with a rescued crossbreed, so her knowledge is not extensive. From a training perspective it was all very basic. On the way back from our walk, she said "I don't think my training methods are going to suit you". She was very cold with Brie, she didn't touch her at all and declined to walk her on the lead when I offered. I'm not sure whether she felt intimidated by Brie or by me (or by both), but I could say that we both (metaphorically) had our hackles raised by her. My partner was on the walk with us, but at a distance and also noticed that she didn't go near Brie, she seemed out of her depth, as if she wasn't confident around dogs of this size. I almost feel conned by the claims on her website; she specifically mentions having an interest in LGD and large guarding breeds, but the reality didn't seem to reflect this at all.
Maybe I'm being unfair. My cousin did some training with a couple of the top behaviourists as part of her vet med course, she said the top woman, who charges thousands, is oddly cold and aloof, and has "lackeys" that handle the dogs. So maybe this is normal for trainers/behaviourists, perhaps they don't like to be hands on - I suppose with a reactive dog it's understandable...
But I don't know, I still think there's a lot of these people that aren't sufficiently qualified.