In its last period of usage it was take-off only, and props only. The authorities had to of course paint the Northolt and Southall gas holders as pilots had been known to mistake the latter for the former when using 23 to land....a PanAm and Lufthansa 707 landed at Northolt by mistake because of the confusion!
Occasionally the wind would shift and 23 aircraft would veer away and then do a sharp turn over Hounslow West to land on 28L. Or a 'plane would be shifted from 28R to 28L about two miles out, right over our house! The Outer Marker for 28L I think it was, was an aerial on top of a brick box in the school's sports field in Wood Lane, Isleworth. Never did find where the other Outer Marker was!