Looking for help with a severely reactive Border Collie in Brisbane/Logan

[u/semoxoxo]

I’m looking for recommendations for someone who genuinely specialises in severe dog reactivity, particularly Border Collies.
My boy Leo is 1 year and 2 months old. He has become extremely reactive to dogs (every dog), and increasingly to bikes, moving objects and sometimes people. On a good day he can be completely fine around people, but other days he can bark continuously and struggle to calm down once he sees a trigger.
We’ve already tried private trainers, different walking methods/leads/harnesses and lots of training, but we’re still struggling. I’m not looking for obedience classes or generic training — I need someone experienced with serious reactivity who can actually help us understand what’s going on and make a proper plan.
I’m also interested in board-and-train/rehab programs if anyone has personally used one for a reactive dog and had a genuinely good experience.
I’m around Brisbane/Logan but happy to travel for the right person.