But as you say. That is your experience. With respect, the experience of others, may differ greatly.
It is Shula who runs a riding school and stables. AIR Lilian was just running stables for the ‘housing of horses in/around Ambridge’. I am not aware of Lilian having any teaching (of horse-riding) qualifications.
An earlier storyline, had Christine - who does have that teaching qualification - in partnership with Carol (as I recall) at a riding school in Ambridge. This was the pre-Shula ‘goes horsey’ days, when she was still the estate agent for Berrows(?).