Not really my subject, as a civil aeroplane man, but the Nimrod used the Comet 4C fuselage - or at least the first two development aeroplanes did, as they were the last 4Cs taken from the line for that purpose. I can't remember if all production Nimrods were 4C length.
The huge radome/bomb bay fairing below the fuselage (lost of side area right at the front) would seem to me to be the natural source of any yaw stability problems.
I would point out, when you refer to "Airbus-designed wings," that all the wings of Airbus types have their aerodynamic origins at Hatfield - the first were designed there and later types were designed by substantially the same team, relocated to Filton.