i know this is a very old post but hopefully you'll still have the same email.
if not, any other input from other people on this forum would also be appreciated
I have exactly the same problem with my mare i have had her for a year and have worked through lots of issues with her.
I still have a problem with getting on her, its, like you said, the initial 30 seconds, if she panics and reacts, shes off and so am i, if she doesnt, i can relax and know...