Hi Martin,
Welcome to the forum.
Basically the original Sammio Spyder was based on a Triumph Herald, then this was renamed the Ribble Pilot.
The Sammio Cordite was based on a Triumph Spitfire, then this was renamed the Ribble Navigator.
But for added confusion, there was a MkII body shell made for the Navigator.
There is a bit more background on the "Useful Info" thread at the top of this forum.
Hope that helps, Paul.