I don't really know much about it but the anomaly between the Sea Vixen and the Bucc might be explained by the hard work of the late Marcus Edwards. I understood from him that FR Aviation had taken over authority for the design of the Vixen when they were modifying them for use as target drones. Marcus used his persuasive powers (or blackmailed) his old Navy bosses, now at FRA, to continue to act as the design authority. This removed one of the objections by the CAA. . .. .Sadly Marcus died before he achieved his ambition to fly his beloved Vixen again. Still its good to be reminded of my old friend when I see it flying around EGHH in other capable hands. Long may it continue to fly.