Possible Clues:

• Small cupboard, one with a key?
• Cupboard
• Gym's storage compartment
• Dressing room feature
• Safely secure the ends of weedkiller in cupboard
• Box at the gym?
• Small clothes cupboard
• Cupboard showing built-in clock, erroneously? On the contrary
• Philosopher reading maybe in a secure compartment
• Troublesome clerk took in head of The Cabinet