Tappers Dad is absolutely correct. The aircraft was ??229 (I didn't bother with the letters in my log book). The intention was to go for the flare towed by a Jindvik over Cardigan bay but because of the sighting device the missile acquired the Jindvik so I suppose you can actually say that a Nimrod has downed an aircraft. The sighting system was two bits a perspex on the coaming with cross hairs so when lined up on the target it was on the missiles boresight, the sidewinder growl was also present when it had the target's I/R. Further sophistication was provided by a circle around the cross hairs on the rear bit of perspex. When the 707's wings filled the circle it was ideal winder range.