The weekend of 21st and 22nd September is a chance to visit over 800 buildings in London not normally open to the public. Open House weekend also includes walks & tours. A few need booking in advance. Visits free.
See locations at https://openhouselondon.open-city.org.uk/ . Or download the app: [ https://play.google.com/store/apps/details?id=org.opencity.openhouse ]
Locally in West Norwood we have:
Cheviot Gardens extra care housing , 36 Cheviot Rd SE27 0SU 1pm to 5pm
Clockworks, clock museum, at 6 Nettlefold Place SE27 0JW 10am to 5pm
West Norwood Cemetery Norwood High St Road SE27 9JU Tours 2pm and 3pm
The South London Botanical Institute, 323 Norwood Road SE24 9AQ 1pm to 5pm