Water in boot lid, 2010 A4

[Condi]

First post, so hi, and apologies for asking a question straight off, but Im here for some advice.

I have a 2010 A4 S-Line which is getting water between the boot lid skin. This has been going on for some time, but recently rust has started appearing at the lowest point of top skin, near where the lights are. It doesnt happen every time it rains, and I've not worked out where water is coming in from. Removing the rubber stopper in the picture below can drain out the water.

There are lots of posts on here about water in the light cluster, but my light clusters are totally dry - its just water within the boot bodywork.

Can anyone recommend either somewhere to start looking, or suggest what the issue is, before I speak to Audi?

 

[Stonefish]

The light clusters are OK. It is the seal between the cluster and the boot lid. The water pools in the bottom of the boot lid but will run down the boot supports and drench the radio or amp when you open the boot. I removed the plastic grommets in the lower edge of the boot and the water drained out.

 

[Condi]

Thanks, but surely if the seal was the problem the lights would have condensation or water in them, as the rust/water pool is higher than the bottom of the light?

Its a good starting point, and I'll replace the seal as they'll be cheap enough.