Portsmouth is Fanny's birthplace in MP.

Portsmouth is a port city in Hampshire in southern England. It is the most densely populated city in the United Kingdom; the most recent census recorded a population of 238, 800.
Portsmouth is mostly located on Portsea Island. It is the only English city not on the mainland of Great Britain.
Portsmouth was founded about 1180 when a merchant called Jean De Gisors founded a little town in the South-West corner of Portsea Island. Jean De Gisors was a merchant who owned a fleet of ships. He was also a landowner who owned land on Portsea Island. In the Southwest of the island was a small inlet from the sea called the Camber. It was a sheltered place for ships to land and De Gisors decided it was an ideal place to start a town.
Early in the 17th century, Portsmouth was described as a poor and beggarly town. At the end of the 17th century and the beginning of the 18th century, Portsmouth Dockyard began to expand. New docks and warehouses were built. A church dedicated to St Anne was built in 1704. Rows of houses were built in the dockyard for senior officers who needed to be close to their work. A naval academy for training naval officers was opened in the dockyard in 1733.
Today Portsmouth is known for the Museum of Royal Navy, the old warships, historic dockyard, and Charles Dickens’ Museum. Charles Dickens was born in Portsmouth.
“A History of Portsmouth.” https://localhistories.org/a-history-of-portsmouth/