Buying a property with a sitting tenant

Other

I'm thinking of buying a property that has a sitting tenant - he's on an AST with a few months to run, The current landlord says he's a good tenant, and in principle I'm happy to keep him on, but I don't want to get into complications re. deposits or previous agreements. By the time the sale completed, I think his AST will have expired anyway, so would it be best for him to continue on a stautory periodic until I'm the owner, then start a new AST with me? Any other advice welcome.