They are able to bring a locksmith with them to open a locked door without force, They can bring the police along with them but the police are not there so that you open the door, They only there to assist them if anything gets nasty for them but usaly the person living at the house will not realise this and feel they have to open the door because the police are present. The locksmith can not get into a house with a bolt lock on the other side of the door as they cant force the door to get in. They can only pick a lock. If they do come inside the house they have to have proof that the items are the house owners. To avoid this you get a friend who lives far away, possibly abroad to print out a contract signed by them that all items/contence of the house are rented and belong to them, not you. That means they can not take any items from the house as they belong to someone else as far as they believe from the contract paper made by your long distant friend.Obviously there must be contact details on the contract of your friend and for your friend to play along with the story when they contact them. If you own a car or a van, They can not touch that or any item in that. Keep your laptop in the car. They can't take garden items and beds,cookers, basic things you need to eat or cook food with. They can't do anything before they have taken you to court but stand at your door any say lies so much you will beleive. Just don't let anyone in even if they say there the gas man etc, unless you know for sure the gas man was coming round at that time. once there in they won't make things easy for you.