Possible Clues:

• Take drugs inside silent public building
• Collection of curiosities
• Place like the V&A, say
• Keep quiet about employment in the V and A, say
• Exercise adopted in silent place of learning
• Art aficionado's hangout
• These pieces old hat stuff from William Plomer?
• Mother gets exercise in building that can be walked around
• The British, perhaps, ponder limits to unilateralism
• Mother hides advantage of having a lot of old dinosaurs hanging around