No don't get rid of buildings. If the OP does not need the income just leave. If renting out obviously there would have to be a change of use. Tenant would pay business rates if applicable.If you're not using it for farming knock it down, then you don't have to worry about the rates
The car spraying business could end up with a lot of vehicles parked all over the place with a sorted crap everywhere. I imagine a landlord might have to keep an eye on the accumulation of crap that could be potentially be left behind at the tenancy termination.