A further update. I have found some more information and the bonnet lock system on my FF Mk2 is the LHD kit. Quite why it was fitted is a mystery, I have only owned the car since 2009 and it's a March 2005 car.
Anyway, if anyone does have the LHD kit on their car then like the RHD kit you should be able to purchase the whole kit, like this:
However, it's only the plastic connector that was needed. This maybe available from Ford but by good fortune I found a seller on Ebay selling them at £4 + £1 P&P so I bought two and it works. I don't know if the Ebay one is genuine or not but doesn't really matter.
The company selling these on Ebay is Locoser Limited (email firstname.lastname@example.org)