@Loz Whaley Hi there! A few things may be going on here.
If the smell is musty / damp, it’s possible some liquid or moisture may have gotten into your cyclone.
If that’s the case, first, try blasting out the cyclone area with a can of compressed air.
If the smell is indeed coming from the filter only, let’s replace that part.
If all else absolutely fails, you can ask local support for options on replacing the “main body/cyclone”.
@Loz Whaley moisture in the vac. Either suctioned up or on the filter still after a wash.
Rewash the filter and give the clear bin a wipe out with a anti-bacterial wipe (let it dry).
If that fails, Adam’s advice stands.