I agree with Abby. 45 minutes of cantering for a horse that hasn't been worked in a year is really unbelievable. You want to condition her up to intense workouts, not start her out on intense workouts. Besides, I think that's wayy too much work for any horse anyways.
Again, I think it's really important that she listens to you when she hasn't been worked out.
I'd start her on an exorcising program (on a lunge line, about 10 mins trot, and a couple minutes of canter both directions. Or riding her w/t/c), that might help get her silly willie's out in a safe, unharmful way.
I'm glad you're addressing this problem, though! I know some people who don't fix bad habits and it drives me up the wall ahaha.