If it has been used as something before it’s a brown field site... if there is no contamination I don’t see why you shouldn’t get planning tbh. Is there a house there? If there is you can build a stable within the curtilage as permitted development
I am currently looking for a horse and I confess I'm fairly picky. After a long time of 'making do' with other peoples cast offs and project horses with 101 thing wrong with them I have the time and money to buy the horse I have always wanted.
I am in no rush to find him/ her and know exactly...