Everything is going mouldy in my shed

[HenryGregory]

Hello,
I have a 2 year old shed. It is nothing special, felt on the roof seems good, but I am finding that mould has been forming inside.
I treated the entire exterior with Ronseal paint in summer 2019 when it was one year old.

Is there any way of stopping this?

There small spots on the roof:

I had already wiped these handlebars, but you can see there are still some bits of mould on them:

 

[foxhole]

Needs ventilation, mold spores are floating around in the air , you need to prevent them settling to avoid mold.