I think the plane being referred to is a Cargologic 747 (G-CLBA) which departed Heathrow for Atlanta, then flew some race tracks over Bletchley, altered course to the SE, flew some more race tracks off Harwich, then flew on and diverted to Frankfurt. All at relatively low altitude - 9000 ft, and speed - 300 kts. Race tracks are usually flown to dump fuel and reduce the landing weight of the plane. Suggests that maybe a technical problem manifested shortly after takeoff.
Ken Munn ● 2041d