315802 was out on the last day to Chingford, so just shy of 40 years. I guess all the remaining units have cleared 40 years service now.An esteemed source on a former Yahoo Group confirmed it as Monday 8th December 1980, on a day very much overshadowed by a certain assassination. The first units in service were paired as follows: 802+811, 806+804 and 808+809.