A shopping centre under Cavendish Square?

A public park just behind Oxford Street’s John Lewis store could be turned into an underground shopping centre.
Cavendish Square was laid out 300 years ago as a garden, but in the early 1970s, a 3-storey underground car park was built underneath and that’s still there today as a car park.
The car park could only exist as the London Squares Preservation Act 1931 which stops the public gardens being redeveloped didn’t prohibit subterranean developments. The only difficulty they h