Request for Advice on Canvas

Hi all,

Last year after rain, unbeknown to me my better half folded up our 4WD Camper whilst damp after letting the kids & their friends sleep in it for a night.

The result being after opening the camper six months or so later, the canvas on the roof is covered in mildew. It's only a cheap EZYCamper so I accept there's better quality canvas used on other campers. Nonetheless it's served us well thus far.

Years ago my father scrubbed the roof of his annexe after parking under a magpies nest for four months & in doing so compromised the canvas. It never looked the same again so I''m keen to avoid a similar result.

So I'm open to advice on how or should tackle the mildew & ideally what products are available to help me.

Please advise & thanks.