A FINE art expert from the BBC's Antiques Roadshow is suing a University of London college, claiming more than Pounds 200,000 in damages relating to alleged unpaid commission for the sale of a Constable oil sketch. Peter Nahum has taken Royal Holloway College to the High Court over an unpaid bill for Pounds 196,812. Mr Nahum helped find a buyer for the sketch "View on the Stour". The college sold off three of its 77 paintings in 1993 when it needed to raise some money for building work. As The THES went to press, the hearing continued.