Just been speaking to my Dad on the phone, a stone hit his windscreen today and chipped it. He has comprehensive insurance with Aviva (possibly their premium package, he couldn't remember) so would either pay £10 excess or no excess if he has premium.
Information online though seems vague about whether windscreen repair claims need to be disclosed at future renewals... So although it won't affect his no-claims we're unsure if it will affect future premiums? 
Would he BU or unwise to get it fixed for free at the point of repair? Has anyone had a premium go up significantly following a windscreen repair claim?