Fredpuli47 correctly states that circumstantial evidence can be used to prove that something is stolen. e.g. if someone buys a �200 mobile phone for �10 from a guy in a pub, that might well suggest
(a) that the phone is stolen ; and
(b) that the purchaser would have reasonable grounds to suspect that the phone was stolen.
Such circumstantial evidence could be used in a prosecution, even though there was no direct proof that the phone was stolen property.
However, there's nothing in your post which suggests that the police have any relevant circumstantial evidence. For further information about the law relating to handling stolen goods, see here:
http://www.cps.gov.uk/legal/section8/chapter_a .html#12
However, I still believe that your real concerns should relate to trading in counterfeit goods, rather than to handling stolen goods.
Chris