Abandoned Stuff-advice sought

Other

I finally got possession of a property back in July where the tenants had lived for 20 odd years. They left behind loads of stuff, but never came to collect it, including 2 vehicles and 2 caravans. They were advised at the time they could come and take their things- but never did. I have started clearing the site now, but they have just made contact and now want access to get their stuff. I dont mind them taking it away, but can I charge for storage, and can I make them take all of their junk away, and not just cherry pick the stuff they want? They also made off with two new storage heaters? 

Not sure of my rights here, or what the legalities are, so any help is appreciated