Thats right, Pan Am into Northolt was 707, not 747.
Going much further back, BOAC landed Constellation at Nairobi West ( now Wilson) instead of Eastleigh ( which was the international airport pre the existing one at Embakasi). Runways were on similar heading and aircraft broke cloud to see a runway in front of it, so down he went. It repositioned later without passengers. A good account appears in Peter J Davis book "East African-An Airline Story".