My son ran against their prep-schoo (X-Country) several years ago. It seemed nice. Very small. I have not heard anything bad about them. The fact that pupils can take their own horse, if they have one, would tend to indicate that they cater for the individual, and not the herd.
I went there as a pupil over ten years ago, and it was the most fabulous experience. The school is very small and friendly, and is 'different' in many ways. It is a Round Square school (google to find out more) and as such is very hot on outdoor education, not just a token DofE scheme, but is properly embedded into the whole ethos. It's not too pushy academically, and does cater well for the less able, being small meant that the staff and student relationships were exceptional. It is quite arty/musical and also sporty in the sense that students are encouraged to 'have a go', and being small, many students have the chance to represent the school in something or other. The farm is a really unique point, and if you so wished you could take your horse, but also you could be doing lambing duty, showing animals at various country shows, or be the pupil farm manager. The grounds are beautiful. Sixth form boarders live in log cabins and have a great deal of responsibility for themselves, seems like a great preparation for life after boarding school.