The rest of her description, is no doubt correct, too, but I confess would be hard for ME to do without taking up rein contact again. That is because I don't have the training in dressage , I suppose. I mean half halting and doing a lot of transitions with out the reins takes riding with the body and seat, and I know this is the correct way, but it isnt' easy.
You might also try using something without a bit for awhile. My friend's horse started to curl behind the contact and become dishonest in his forward, sucking behind the leg. She put him in a sidepull and this helped tremedously.
But to cure his fear of the bit , you do have to work in the way Anabel has described.
Lots of foward.