Hot summer and startup on the AC system gives a very bad smell on many JE's - and so have been the case on our 24v since we bought it.
But now i was determined to fix this problem, and the solution with TUNAP Contra sept Disinfection Cleaner for Air Conditioners ++ seems to have done the trick! Hopefully it will be good for a long time now.
I created a post on my forum with some description and photos of the operation - the topic is in norwegian but the pictures pretty much tells the story.
http://www.renaultbiler.no/forum/viewtopic.php?id=3659