You want Speedo to associate the litterbox with all things tasty and wonderful, not with reprimands and punishment. If she's making a few mistakes, that's part of learning. Stock up on paper towels, and get out the broom and dustpan. If she's making lots of mistakes, she probably has too much freedom and not enough supervision. Give her as much freedom as she's able to handle, and confine her the rest of the time.
Unneutered rabbits have difficulty adapting to life in a human household.
You should see an improvement in housetraining within 2-3 weeks of having your male bunny neutered. With females, the behavioral benefits may take several months to be noticeable. The more time your rabbit spends in a plastic tray filled with rabbit-safe litter, the more accustomed to using a box he will become. It doesn't matter whether he's actually eliminating in the box or simply sitting in it. Many rabbits even sleep in their litterbox.