Sorted.

Going through the manuals/guides that came with my car I am pretty certain that mine was factory fitted with the Land Rover Watch Stolen Vehicle Tracking System. Page 6 of the user guide states "If no tag is detected an audible warning will sound inside the vehicle for approximately 10 seconds" The tag is a fob you're supposed to have on you when you drive the car. Will have to see if I can get it transferred / re-registered to me.

Nice you got it sorted  BETTER looking half of the famous Twinlanders
The wanna be other half - http://www.freel2.com/forum/member-carriec.html