I know exactly what this is mate as I had the same. Mine was going off in the early hours. I used to sit in the car and see it say the boot is open when it wasn't. I took the battery lead off in the end to stop it going off.
The problem lies with the boot micro switch. What happened with mine is that the rear washer jet was leaking onto it as the pipe came away from the I side of the tailgate. I tried to blow out the water with an air line but it was still the same until I bought and fitted new boot micro switch (comes with boot catch).
When you fit it make sure all the pins are there and not corroded/fallen out. Also check rear washer pipe is connected securely.
HTH
The problem lies with the boot micro switch. What happened with mine is that the rear washer jet was leaking onto it as the pipe came away from the I side of the tailgate. I tried to blow out the water with an air line but it was still the same until I bought and fitted new boot micro switch (comes with boot catch).
When you fit it make sure all the pins are there and not corroded/fallen out. Also check rear washer pipe is connected securely.
HTH