Thanks John for looking up the details in your Haynes manual. It's interesting there's a difference between a 2006 and 2007 Roadster engine.
Further research revealed the below entry on Wikipedia which may suggest it is a Duratec engine, initially designed in the early 1990s as a 2.5 litre that eventually was enlarged to 3.0 litre and the design had some input from Porsche!.
https://en.wikipedia.org/wiki/Ford_Duratec_V6_engine.Either way I'll take the engine number and visit a Ford dealership to see if they can confirm but it's probably a chain like yours.
