The first theft took place on the viewing day before their October sale when a Tudric-style, cabochon-set pewter and green glass flagon went missing. The second theft took place on March 24, when the pair of 6in (15cm) Berlin oval plaques went missing at about 4.30pm during the book auction.
Anyone who has information that could help trace the suspect should contact Sussex Police on 0845 607 0999 quoting crime reference number ES1/027342/10.
