You're absolutely right, what can riders aged between 13-18 learn from riders in the expert class with riders like Baker, Danby, Thorpe, Vesterinen, Pearson (this years top 5) plus past winners sam haslam, james lampkin, andy huddlestone, darren brice, david knight plus other riders like alexz wigg, lee sampson, shaun morris, michael brown.....do i need to continue? I do believe some of those riders are also ACU coach's. Sorry to be a bit blunt but i think you were out of line there.
The fact is that the acu do have problems with fixtures and i do sympathsise with you but im sure a compromise can be reached. If it comes down to a clash with an adult british champs round then it should not be a problem as it is an ADULT brit champs round and youth can only ride as guests anyway.
Good luck in sorting this out. Scarboro youth trials are a big part in our top riders history so it would be a massive shame if you decided to not run your event.