Here is the link if you would like a look:
http://www.westsuffolk.gov.uk/Busin...HDC-Driver-and-Vehicle-Licensing-Handbook.pdf
Page 19-Vehicle is what I read but have just noticed toward the bottom that the rules are repeated for private hire taxi's that are the same as Hackney taxi's except the roof sign...:shame:
So in the end it probably is a taxi given the time.
What I'm surprised about is that the man on the bike is likely local given the he's on a bike and he looks smartly dressed like a doorman or security. If he was riding round BSE centre (it was said he was riding around Cornhill square when the first image was released) talking to taxi drivers etc then someone must know him.