Ideally, both riders should be proficient at Walk and Trot, possibly with Canter experience.
 
Whilst we can teach 2x Beginners together in a Semi Private Format, ideally we would need 2 Instructors, so each person gets the attention needed when you first start riding.Alternatively, a single instructor can teach 2 Total Beginners together but handlers would be required until Walk and Trot is established and the riders are experienced enough to control the horse themselves to a basic level.
This does require additional staff, and an additional fee might be required for Total Beginners, and subject to availability which is highly limited. So this isn't a guaranteed service, but can sometimes be arranged.

This is determined during booking, ideally all assessments would be taken in a Private format, 1-to-1 with an instructor. We do allow experienced riders (years of experience, own horse etc) to take an Assessment Lesson in a Group Lesson, providing they feel confident enough.
You must be able to demonstrate proficient Walk, Trot and Canter, as an example, the first 2 motions, and probably the third  with no stirrups whilst doing exercises. If you can't do this, or think you might fall off, then a Group Assessment isn't suitable for you.

We do have BHS qualified instructors, and staff training towards higher levels, we feel it's important for riders, staff and anyone with an interest in horses to consider completing the BHS exams, but exams are no substitute for experience, which all of our staff have plenty of.
We're an extremely popular riding school, and we've done it without being BHS or ABRS approved. Although we're considering it, as there is an increasing interest by the younger riders and instructors to take exams.
Additionaly, we've trained many riders over the years at our center to take the BHS exams at Exam Centers, and they've passed with flying colours (even some in 2009), so we're obviously doing something right.