Had my repair carried out at the beginning of the week, as there was also a delay with parts.
The leak was getting bad and water would come through in about 5 different places. Even dripping down onto the passenger seat.
They replaced the wind deflector and 'some other parts', but it's been below freezing all week, so I haven't been able to test it.
When I got home I tried the roof and it only moved about 5mm and then closed itself again.
I don't think it was iced shut as the car was very warm inside, so after an hour I went back out and gave it a gentle push while I pressed the button.
It opened fine after that, but seems a tighter fit now.
They had heaters in the car for an extra day to dry it out, but it still smells a bit nasty inside.
I'm sure it's getting better as it dries out more though.
Its strange as I had no issues last winter.
I've no idea why it suddenly started leaking. The drain holes were all clear apparently, but the wind deflector had deformed a tiny amount they think. This has something to do with how the water travels.
The warranty paperwork I recieved said
"Carried out replacement of Wind Deflector & Seal as per Audi TPI 2059326/2 Due to water ingress".
If yours is leaking, then get it in to be repaired ASAP.
You won't always notice the water as it travels down the A pillar and isn't always visible, but it will just get worse.
If the carpets get too wet then it'll mean stripping the interior to get the carpet out to dry. If you catch it early enough then they won't have to do this. I was glad mine didn't have to be pulled apart too much.
I was also lucky I have a black roof lining, as a lighter coloured one would show any staining I imagine.