When I open my boot rainwater drips inside the boot lid from where the two plastic bits of trim join together, and then drips inside the boot. I was wondering if anyone had experienced this and there was possibly a fix? Thanks in advance.

My sister has had this problem but rather than being caused by rain water it was due to the rear washer being blocked and leaking into the gap behind the trim. I'd take the trim off, and watch to see if it's leaking with you when you press the rear washer button. If it is, try giving it a blast with some compressed air or a poke with a pin or something.... might be blocked.