Insurance
If you have fully comprehensive motor insurance you can usually claim for windscreen repair and windscreen replacement on your policy. In most cases it will not affect your no-claims bonus.
If you just need your windscreen repaired then usually this is free of charge to you. However, if you require a replacement windscreen you will normally have to pay the insurance excess (usually to the windscreen service company).
This will usually cost you £50 - 60 depending on your excess. You pay it direct to the windscreen company in most cases.
