I emailed the seller re the rear lamp unit and asked whereabouts he was in 'london', replied 'north london' so I asked him to be a bit more specific. Note; did not ask for a postcode or street address, just an area: Tottenham, Barnet etc etc. No reply after 5 days, so obviously not happy about items being collected! Re the panniers; if you click on the seller's feedback rating there is a feedback for the panniers with a picture of them. Might be of interest to anyone who's lost some panniers. I suppose the answer would be to ask for the regn number of the bike that was being broken, then one could do an HPI check on it.
Not good but not hard evidence either. If the plod were interested they could get to him. More likely he's running a bike breakers on the side and thinks he can hide from tax collectors.