On the face of it the DVD comments seem credible.
It's also plausible that the man in the CCTV footage is known locally and to the police, but nothing can be proven. I suspect he was checking for a light to see if she was at home. Her naivety has been mentioned by her sister and her only long term relationship ex. She thought she could stay in good terms with the men she had affairs with; she still spoke to the man who lost his marriage just January that year as a result of their affair. This certainly does seem naive imo and quite clearly, she was wrong to make that assumption.
As Claudias moral character has been portrayed in a somewhat less than flattering light, this has contributed to people not wanting to help by providing information that they may have done in other circumstances. If it happened now, people might think differently, as attitudes towards women have certainly changed in the last few years.