my advice to you would be
A) do you like the instructor.
B)does she/he bond with your horse.
C)is she/he qualified.
D)do you enjoy their lessons.
E)does your horse agree to her teachings and her lessons.
good luck in finding the right instructor though!!.
:)
personally i would leave this yard and go to the other one because it costs less and it also has better management for the horses and you, but if you are comfortable about the other yard and your horse is content then you might as well stay there. Ultimately it is up to you! :)