Right I got the pollen filter out last night and it didn’t smell bad and wasn't wet or anything? I have ordered the upgrade one from puravent.co.uk but I doubt that is going to help with the smell.
I also took out the passenger and driver side air vents and had a look and smell inside the holes. I could smell something but I couldn’t see anything that could be causing the problem?

And I certainly didn’t see any dead rats ha ha!
I’m really stumped and it is driving me mad. It is really bad when you have the blowers on the Lo temp, but the air con off. When you turn the air con on it kinda goes away. This is all well and good during summer, but come winter I will freeze coz I don’t think my heated seats alone will be of much use. Also the extra fuel consumption is gonna suck.
Be really good if anyone has any other advice, or should I take it to the dealers? The car is still under warranty so if anything needs changing or whatever it should be free.