Just found light condensation along the bottom of the xenons & need some advice, the fact they're both like that suggests there's no cracks & a visual inspection confirms. I take it this is something a dealer will fix?

Condensation behind the headlamps isnt unusual, its a preasure difference between inside the lamp unit and atmospheric preasure. Obvisouly if you steam clean your car they might possibly leak water aslong as there not really bad there fine. If you take them to your dealer they should help possibly take photos for warranty evidence and even carry out headlamp fixing kit modifications suplied from SKODA.

I have the same problem on mine.

I have a 3.2 gsi Vectra which does this very occasionally. The main reason for it is that the Hid lamps don't use (or generate) nearly as much heat as standard filament type lamps, and the condensation takes longer to go away. It is always worth taking the headlight out to see if the rubber temperature equalising tube has not been squashed when installed into the car. A sqquashed tube will prevent the lamp units' temperature adapting to atmospheric changes quickly.

Mine have been doing it this winter in the lower corners of the lamp, surely once there is some heat generated by the lamp/engine it will be cleared, but is the light a sealed unit or is there a vent?

I've had a number VAG cars with Xenons, so do mates / members of other Formums I knw and all do or have at some time had misting / condensation behind the glass.

They're not sealed units so moisture rich air can get in there, be warmed by the bulbs and then condense when the temp outside drops quickly.

Nothing to worry about unless it dripping wet !!