Rubber seal around the boot opening not the door can let water through where the check strap is located, I have added some tiger seal so as to heightened a channel to divert the water away from the bottom of the rear door seal on both sides, so that the water flows down both sides but doesn't go along the bottom of the seal. It seams to be working ! also check about half way down both sides of the seal where their are drain holes they can also be blocked causing water to seep into the boot area. Also I removed the seal and reapplied it to make sure it was all located tightly and that it wasn't damaged crushed or split anywhere.
