Of course there was 'Pippa', who was initially a V-bomber pilot and was subsequently unsuccessful at TWU during FJ cross-over training after the Vulcan left service. Rather than go back to being a ME pilot on another type, he elected to become a FJ navigator and was quite successful, if less than popular.
But when he took a Gp Capt position with the Air Cadets, presiding over the death of Air Cadet gliding, he wore his pilot badge rather than his nav brevet...