The setting is worthy of an Andrew Lloyd Webber musical. Occupying what was once the vault of a 19th-century bank building, Le Spa is lockdown luxury. A heated robe hangs at the ready in the individual changing suite. A wrap of pulverized green coffee swaths the body in a grainy antioxidant substance that claims to fight cellulite. A celebrity favourite, it doesn’t come cheap – but it works, even for people who might have denied they had cellulite in the first place.