Keep persisting with her!
If she's quiet to handle in the stable, it will eventually come right.
I have a chestnut mare who came 'wild' off the Forest last year, much the same kind of reactions! When I have her 'enclosed' in a small space, I can do almost anything with her, but she can throw the most amazing hissy fits about 'being held' if there's any room that she can break away into.
Do you have a round pen or small schooling area that you could work with her in? Something where you could attach a lunge rein, for example .... but if she ran, she could only run in circles around you because the fences are closer to her than the length of the lunge rein? If you do, try that, and every time she slows down, praise her like mad. If she'll come to you from a call, with gentle pressure on the lunge rein, give her a treat and lots of fuss, etc., until she realises that the lunge rein is just a method of communication.
Try also putting the lead rein on her headcollar when she's in the stable, giving her a treat, then taking it off again. Do this loads! She may learn that lead rein = treat.
Best of luck with her
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