20176 & 20043 pass Clay Mills (Hargate) in miserable light on 17 May 1991 with the 6D56 11:29 Bescot to Toton departmental working. Note the 'Thunderstruck' name and lightning flash below the headcode box. By a strange coincidence, I saw this same loco, with a different classmate, heading in the opposite direction at this location a few months later.