A duver is an Isle of Wight

Isle of Wight

The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...

 dialect

Dialect

The term dialect is used in two distinct ways, even by linguists. One usage refers to a variety of a language that is a characteristic of a particular group of the language's speakers. The term is applied most often to regional speech patterns, but a dialect may also be defined by other factors,...

 term for an area of sand dunes. The name has become part of place names on the Isle of Wight, for example Dover Street in Ryde

Ryde

Ryde is a British seaside town, civil parish and the most populous town and urban area on the Isle of Wight, with a population of approximately 30,000. It is situated on the north-east coast. The town grew in size as a seaside resort following the joining of the villages of Upper Ryde and Lower...

 is the street which used to run down to the duver.

There are relatively few dunes on the Isle of Wight, and some have been reclaimed or otherwise lost, meaning that some places which bear the name duver are no longer sand dunes. The largest surviving example is St Helens

St Helens, Isle of Wight

St. Helens is a village and civil parish located on the eastern side of the Isle of Wight. The village is based around village greens. This is claimed to be the largest in England but some say the Village Green is the second largest. The greens are often used for cricket matches during the summer...

Duver.