I've seen much here and on VWVortex about the importance of maintaining the roof seals. However, most or all of the postings are quite old and refer to the original version of the car.
I own a 2013 Sport*. I can't find anything in the current manual like there was in the earlier manual copied...
I've 30ml bottle of genuine krytox roof seal lube for sale surplus to requirements if anyone wants some - well below dealer price at £29.99 delivered. Ebay 200479857243
UPDATE 7th JUNE - NOW SOLD