Moomoo, I am not sure what college would be good but I can tell you one thing for sure that Gloucestershire whole area is Royal. Specially horse riding places in Cirencester are related to Prince of Wales, infact I think he and his sons are members of Beaufort Polo Club in Tetbury (Beaufort Polo Club). I went there to play polo but found out that you have to have your own horse (doh!!).
The place where I go is Summerhouse Equestrian Centre (New Page 2). There website is not that good, I offered help to their MD (building site for no charge) but she said she'll going to get it done by some other company.
I have no idea if they have livery or not, mainly because I am not "horsey" litterate. I hardly understand things about horses. All I know how to ride and take off saddle from the horse. That's about it.
When are you starting your college? And where about? I can then see if I can find something out for you.