If possible, arrange a visit to Shirley Windmill when the wind is up. You may see this structure in full swing!
You can keep your wallet safely in your daypack, because it won't cost a thing to explore Shirley Windmill. Located in Heathfield, you'll find some cool attractions not far from this wind-driven milling structure. Why not explore Crystal Palace National Sports Centre, Selhurst Park Stadium and Crystal Palace Park too?