If the historical Sea Venom became the Sea Vampire, what aircraft would then receive the Sea Venom name?
Short answerProbably an intermediate gun-armed design rather than an early copy of Sea Vixen, because the later fighter's shape and role depended on missile and radar development.
NotesA neat name swap would not make the historical Sea Vixen appear early under the Sea Venom name. Aircraft development is evolutionary, so an earlier design changes the experience and systems available for the next one. Sea Vixen depended on radar, missiles such as Red Top, and an airframe arrangement built around those systems. A plausible intermediate aircraft might resemble a proto-Vixen but remain a conventional gun-armed fleet interceptor. A later Sea Vixen II could then adopt the all-missile configuration once the required avionics and weapons matured.