Ask H&H: agreement to rent land

A neighbour has asked if he could rent our 10-acre field. He wants to put some stables up, and says he will apply for planning permission. Our solicitor, who is not horsey, is not keen for us to put anything in writing as it would put any problems on to us. I am sure there is a way round this and would be grateful if you could suggest what we should include in a rental agreement. I would also like to know if our neighbour can apply for planning permission for our land, and what type of permission he may need.

DH