The Longbow isn’t a missile. It’s a variant of the AH-64 Apache attack helicopter, which uses Hellfire missiles.
The Stingray isn’t a missile. The Sting Ray (two words) is a British naval torpedo.
The Tomahawk is indeed a missile (though originally a type of axe), as is the Exocet (not Xocet).
We’ll probably never know. And it’s easy to over-think it. Webley’s maketing department was probably one guy trying to decide what the kids would think was “cool”. It appears that in the 70s and early 80s that bloke was an aeroplane enthusiast.