Condensation

[Lee S]

2 years ago, I noticed some light condensation in the clear portion of the rear driver's side inner light lens (2010MY D3) and on closer inspection there was a hairline crack in the lens. Sorted, so I thought. Went back to the dealers and got them to replace the cracked lens under warranty. The new lens now has even worse condensation in this clear portion, to the point there are large droplets in there.

I went up to the highlands last year in May and when parked at the top of the Cairngorms, noticed that it had all gone (pressure drop with temp rise maybe??). It was clear again. This lasted until about October or November of last year and then it started getting worse again and now the droplets are back. No other rear lens does this on my car.

Is there an issue with this lens inside (broken seal/crack, etc) or is there any kind of removable cover or plate that may not have been fitted correctly (are there actually any incandescent bulbs in there at all?) or is there any way I can dry it out or get some silica gel in there without trashing it? Anyone got any pics of the back of one? Bit bad on what was an £80k+ car.