Technical door alarm sensor

[blinkyspoogle]

a friend, whilst clambering into the back seat, managed to pull off the passenger side door seal which, as a knock on effect, has dislodged the alarm sensor in the door.

so now i have to just use the keys to lock it, then to get in and start it i have to unlock it with the key, then arm and disarm the alarm to get it to start due to the immobiliser

i don't suppose anyone knows exactly where this sensor is located - i don't want to just glue back the seal thus ****ing up the alarm for all of time

any help anyone can give would be a great help