The 17in x 2ft 1in (43 x 62cm) watercolour over pencil was described by the auctioneers as "exceptional in every sense" and, against a £500,000-700,000 estimate, it duly attracted interest from a number of key players in the market.
The buyer was the Canadian billionaire businessman and collector Baron David Thomson of Fleet, a patron of the Art Gallery of Ontario, who saw off interest from the London dealer Guy Peppiatt.
The vendor - identified within the trade as controversial fertility treatment doctor Professor Ian Craft - had purchased the atmospheric work at Sotheby's in November 1991 for £178,000.
The price here represented not just a significant return on investment but also a dramatic new high for Cozens, easily surpassing the artist's previous record of £240,000 for Cetara, Gulf of Salerno, Italy at Christie's in November 2004.