Mobile phone law came into force 1/12/2003.
Therefore if any vehicles are visible in the programme with a registration mark of 04 (used from 1 March 2004) or later, you have him. Even if they're all pixellated out, look for a current model Ford Mondeo, Vauxhall Insignia etc for proof.
Ch5 might argue that the van was on the back of a low loader for the interior shots, but I would call BS factor 10, and so would any decent prosecutor.