UK Landlord Forum / Life

Hi, we've found ourselves in a tricky situation. We carried out a pre final inspection and found the tenants have packed up most of their belongings and have left the property totally unsecure, keys left in the door locks (on inside) and all windows opened.
We carried out inspection, closed all windows, locked doors and informed tenant, by phone and in writing, that they had contravened their contract. Is there anything else we should do? If this happens again, would they be liable if the house was damaged or if squatters moved in? Advice would be much appreciated.