Thank you for the response, just to update:
I tried scrubbing it to death with washing up liquid/brush.
I tried Fenwick's awning cleaner from Amazon.
I tried diluted bleach on a small area.
I even tried a small amount undiluted bleach.
Nothing has budged it at all.
I really have no idea what these stains are. If it was some sort of mould the bleach would have killed it.
It almost looks like kind of luminous rust marks, but there's literally nothing in the awning that it could have come from, it's practically brand new.
Anyway I'll probably just leave it at this point. Unless anyone knows of any magical potion I could try.
)
