Is there a wonder produce that reduces condensation on a raincover?

[ImNotaPheasantPlucker]

I have a double Mountain Buggy Urban.

Out and about in the pouring rain yesterday (understatement of the year there!) with two hot bodies in the buggy the raincover steamed up immediately. The more their view fogged, the more they complained, the more it fogged, the more they complained ......

I wondered if anyone has heard of anything to prevent this happening?

Apart from making more air holes in it I have no ideas... doesn't half p them off though does it!

The only things that would stop it building up would some kind of coating that you can't use with kids, so the only other option you have is to take it off more often to air or to make more holes in it

I made more air holes with a hole punch, at the sides at head height.
Different buggy though.