They cannot take what belongs to another person, but the onus is to a large extent on you to prove the items are someone elses. Just saying, "oh thats not mine" isnt going to stop them. You need to have proof of ownership i.e receipts for purchase etc. Some bailiffs are good, others unfortunately not so, and are less inclined to listen before acting. If you are going to let one in to assess property, i'd advise that you ensure you have a list ready detailing all the things that are not yours and the evidence to support that, ready in advance. It will make life easier for everyone.