I one word, don't. I have 14 acres, barns, stables and I do not have liveries because they are better ways to lose money and have sleepless nights.
The amount of money needed to set up and run a yard, then the on going upkeep you would never be able to charge enough to cover you borrowing and would end up subsidising someone else's hobby.
Some near me has got planning for a stables and yard but no house, just looking at the plans it will cost them £15,000+ to put in water and electric, I know because we have just moved our electric supply and it cost £4500 and the electric was already there. My neighbour is building a small bungalow and if he wants mains water it could cost him £150,000 and £14,000 for an electricity supply.
So even if you get planning on agricultural land, and that a huge if because if the farmer has sold it as such he has a good idea its rubbish land and he can not get planning permission, it will cost a fortune.