What I find more complicated is horses that appear slow (or lazy as you call them) and then they are extremely reactive.
You've just smacked the nail on the head if you wanted to describe Mitchell... Want to come over to nz and gimme a hand
But back to the tied up business.... What if, instead of forcing the difficult horse to be tied for a long period of time to teach him/her a lesson... I know that some people "desensitise"(sp?) horses to floats by working them by it, and letting them learn that when they are by it, it means they can rest, so they think it's good.
So what if you were to work the difficult horse, and let it realise that being tied up means rest, by only letting it rest properly when it is tied up?
-Just a thought :) if it even made sense