Bitting advice please

[MegaBeast]

For a sensitive mare who whilst is quite controllable out and about does gallop long and low and I'm finding I can't push her up and together as I'm unable to contain the energy produced. She's currently in a D ring snaffle and flash noseband. Thanks!

 

[Paint it Lucky]

Have you tried really sitting into her, leaning back and squeezing with your legs (quite firmly) whilst at the same time holding with your hands to try and bring her together? Prehaps try cantering up some hills like this and doing lots of transitions to get her listening to you more.