Jumping flat and rushing fences

I have recently leased a new horse. She is young (9) and was used for a drving horse. Hasn't been shown in eventing for a few years, and im looking to do beginner novice this year. Lately in my Pony Club lessons she has rushed her fences and jumped extremely flat. She doesnt listen to my half halts either! What can I do!?

Sounds like she's just running on the forehand, you need to pick her up, leg to hand and balance her. Make her listen to those half halts, go back to just flat work. Trot poles, canter poles. Or gymnastics and make her halt between each jump.
Good luck!

Same exact problem I've been having! My horse used to be the most even paced jumper, but now he RUNS at the jumps

Stop jumping for a while and go back to grid work and trotting poles and avoid one jump situations - spend some time making the horse think about where it has to go next by having a lot of turns
Work on his half halts and shortening and lengthening of stride at canter