Water in both rear lights of 2002 Range Rover

[Fulla]

Hi I noticed condensation building in my rear lights recently. Today on looking closer I noticed I have about a centimeter of water sloshing about.
Can anyone help with a fix for this? Is it a common fault? Can I stop it from happening?
Thank you for help and suggestions.

[RedLeicester]

IIRC from when I fitted my light guards, there were several seals around the back where the wires / bulbs come in, and a tiny drain hole in the bottom. May be worth popping them out (only a couple of screws each side), emptying them out, check the hole (if indeed it's there, my memory is hazy) and refitting the seals.

[Fulla]

Took them off last night. It would seem both have splits in the side. Apparently with the heat they do split over time.
So now I need a new set.....I start my search for some reasonably priced items.

[Kneetrembler]

My 55 Plate FFRR just after I bought it new had the same thing and RR changed them, so maybe pretty common.