I'm no expert on the subjects, but I can never understand why an enterprising model manufacturer can't modulate the build so that both Vampire/Venom Single/Twin seater to be built. Are the engine housings that different? if not, you would need 2 types of fuselage (single/Twin), plus nose shapes, two types of wing & 2 types of fins. The manufacturer could then mix & match parts to make virtually any sub-type of Vampire/Venom from a basic set of moulds!