Tailgate Closed Switch

[dransfield 3]

Hi 

I have replaced the tailgate on my t25 estate. However, when it's closed the car still thinks it's open (interior light on and warning light on the dash). It opens and closes fine and locks if I do it manually with the key. but because the car thinks it is open it wont lock from the key fob (and I have to turn the interior light off so the Battery doesn't drain).

Question: Where is the switch that tell the car its closed properly, I'm guessing its in the lock? Is something adjustable?

thanks in advance