Wroxham is a town in the Norfolk Broads on the River Bure, and regards itself as the Capital of the Broads: see Wroxham
The Ds first go by rail to Wroxham (as Tom sees from the suitcase labels), and go by launch with Mrs Barrable to the Teasel tied up at Horning (CC1).
Tim a member of The Coot Club lives in Wroxham.
Pete gets from Tim that None (i.e. no boats) were cast off at Wroxham (BS17).