They are part of a two-bed luxury apartment in Mayfair, which is currently on sale for £5.6m (for a 116-year lease).
The 2,212 sq ft south-facing property is located on the third floor of a residential building at 10 Upper Grosvenor Street, and was one the home of the Dowager Duchess of Northumberland. But the apartment is just a portion of her home - in fact the apartment was originally Lady Eleanor's "vast master bedroom suite", which occupied its own private floor.
According to estate agents Wetherell, Lady Eleanor loved the outdoors, so a garden style conservatory and outside rooftop patio were added to her suite.
Wetherell chief executive Peter Wetherell said: "We can typically count on one hand the number of these types of ‘homes-with-conservatory-&-patio’ we are instructed to sell each year in Mayfair.
“In the heart of central London outside space is one of the ultimate luxuries. A spacious lateral apartment like this with a garden conservatory and rooftop patio rarely come to the Mayfair sales market."