Arena?? What's the hacking like?
If no arena I would say about £15-20 per week per stable depening on hacking.
If arena I would say you could get aroun £25 per week per stable
I rent a 3 box yard in Hampshire with 4 acres of not the best grazing but yard, barn, tack room, parking, owner lives on site. I pay £200 per month incl. water/elec. No school though which is a bummer!
I rent 8 stables, 10 acres with a school, full set of jumps and storage (large container for hay & straw, tack room and feed room) for £600 per month. Includes water. No elcetric but there is a generator for the lights.