The House can be visited
Marlborough House

Marlborough House is a mansion and country house in London. Located in the Westminster district, it is used as a London residence for high-ranking figures.
History+
The construction of Marlborough House began for Sarah Churchill, Duchess of Marlborough and close confidante of Queen Anne. She desired a robust, simple, and comfortable home. The building work, overseen by Christopher Wren father and son, was completed in 1711. For over a century, the estate served as the London residence of the Dukes of Marlborough. In 1817, the house became property of the Crown. Although there were considerations in the 1820s to demolish Marlborough House and replace it with a new building, these plans were never implemented. Later, the building was inhabited by various members of the royal family. In 1853, Prince Albert established the “National Art Training School” here, which later became the Royal College of Art. After the school moved in 1861, extensions were made to the north side for the then Prince of Wales, later King Edward VII.
Source: Wikipedia · Licence: CC BY-SA 4.0
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 51.5050, -0.1361