I had a real duck pond in the back of one of ours so I looked into all the options.
For condensation only, drilling some holes in the lid, or airing the cubby regularly, is often enough.
If there is defintaely a leak, drilling holes in the bottom treats the symptom but is not a cure.
You can run sealant or even mastik along the top of the plstic trim at the top of the rear drop glass, between the plastic and the body.
I then spent a pleasing afternoon sitting in the boot whilst an assistant ran a hose over the back door. We'd taken the rear door card trim off (instructions are in Haines manual) and we checked the plastic water shedder, etc.
Then you can the try adjusting the rear door to get the best fit.
Finally we succumed to paying our local land rover dealer to change the rear door seal for the newer version. They had to do it twice as thd first time they tightened up the door too much and the seal split within a month.
No more leaks noted, but we did still suffer from bad condensation on the windows.
I solved this by taking up the carpet from the rear footwells and airing it out - water from the boot leak had tracked down under the carpet to under the rear passengers' feet.
Cheers
Blippie