I once got a book from a very distant relative who-was-at-my-Christening-but-haven't seem her-since (you know the kind ) that was all about riding for the disabled. It was most likely from a charity shop or the likes, because it was a bit worn and was published in 1978, so was very dated.

I suppose information must have filtered back to her that I loved horse-riding and she just got the first thing she saw to do with that.