Hi, we have mould issues in the bathroom ensuite and we need to replace an exhaust fan as shown in the pics.
1. How can I eradicate these mould issues for good?

Any suggestions or recommendations please?
2. Could there be something else wrong or need to inspect at first for the mould issues?
3. How much will cost to replace the cracked exhaust fan like to like? Please note the exhaust fan is in another bathroom which does not have mould issues.

Please see pics attached. Thanks.