@greencode; was the previous water ingress problem fixed or is this still an issue? You’ve mentioned removing the mats (as opposed to the carpet?). If your rear speaker seals had failed, then not only can the carpet become water saturated, the sound deadening material under the carpet can also become waterlogged and retain water even after attempts have been made to dry out the carpets in situ in the car. Waterlogged sound deadening material could be the source of your damp smell.
If the air con sanitiser bomb doesn’t remove the smell, then I’d check the pollen filter next - replacing it (if it’s waterlogged) would be inexpensive to do.
Apologies for not replying sooner. I was doing a little testing before replying.
- I used the bomb and whilst that made it smell nice for a few weeks with a chemically/perfumy smell, unfortunately the smell has returned - so that was simply masking the original smell.
- I had a look at the pollen filter (that's the one behind the glove box - right? If so, I did and that was in very good condition with no smells.
- Also whilst the AC was running - when I activated the bomb - I noticed water below the car, which I think indicates that the AC outlets are not clogged and water is running out of the car okay.
- I've checked all around the car for any additional damp areas and leaking issues. The only ones I had originally were the tailgate drainage hose - which I replaced a while back and the rear speakers - passenger side was worse, but I replaced the sealant on both and there's been no water getting in since.
I've also tried to have a good close up smell of the fixed carpets - not checked everywhere as I need space to get down very close to the floor - but I did notice the smell was coming from the rear passenger footwell so I can only presume that's the issue.
So, with that in mind, is there anything I can do to remove the smell or am I looking at having to replace the entire carpet

Any further ideas or thoughts, much appreciated.