By Jennifer Hill

LONDON (Reuters) - Three small, exclusive areas of London dominate the rankings of the most expensive streets in England and Wales.

The highest property prices can be found in Courtenay Avenue in Highgate (postcode N6) where the average is more than 6.8 million pounds, according to the third annual survey by property Web site Mouseprice.net.

Other streets in the same area -- five avenues between the Hampstead and Highgate golf courses -- make up the first cluster of property hotspots.

Ingram Avenue ranks number 11, with an average property price of 5.16 million pounds, and Winnington Road comes in 17th place, with an average price-tag of 4.73 million pounds.

The Bishops Avenue and Compton Avenue, both in the same area, narrowly fail to make the top 20.

The second cluster of super-expensive properties is in the Borough of Kensington and Chelsea, just below South Kensington tube station and demarcated by the King's Road to the south and Fulham Road to the north.

It includes Chelsea Square SW3, which ranks number two with an average house price of 6.44 million pounds, Manresa Road, third at 6.19 million pounds, Carlyle Square, sixth at 5.58 million pounds, The Vale, number eight at 5.44 million pounds and Mulberry Walk, in 15th place at 4.87 million pounds.

The third group of multi-million pound properties falls again in Kensington and Chelsea, but is situated south of Hyde Park on the western side of Gloucester Road and Palace Gate, between Kensington High Street and Gloucester Road tube stations.