Have a 15 cm crack on the windscreen,

No apparent impact just a crack from one side, will one of these kits do the biz, http://www.halfords.com/motoring-travel/cleaning-body-repair/scratch-repair-paint-restorers/rain-x-windscreen-repair-kit
should I try a service, or bite the bullet and suck up the insurance excess,

Cheers

I dont think there is any way you can fix a crack that big, I’d just ignore it till MOT time.

Don’t ignore it your windscreen will not be as strong.

What insurance excess? Ours was done free, and no change in premiums

I would repair with professional repairer but not those repair kit … 😯

Recently, I got professional specialist window polisher (yes, it’s a niche market) to help me polished the deep scratches out of my car windscreen. He had to take a very thin layer of glass off as normal polishing would not do. Need to be very careful or the windscreen would break. I was tempted to do it myself but the cost and learning curve put me off.

According to the window specialist if the crack is located at the side of the windscreen it will definitely break and not worth repairing. However, if it’s in the middle you might be “ok”.

Even if you insurance company does not charge you premium, the next time when you try to insure with another insurance company they will ask you if you made claim before. You will have to say “yes” regardless as some of the ZM insurance companies will not even ask you specific the kind of claim. You claim! You pay good premium!

Oh ya … if the windscreen has too much scratches or there is a noticeable crack you will fail MOT.

Don’t leave it, apparently the windscreen is part of the structural integrity of the car, or so I was told. This might be utter bollocks but it seems to make sense. Also it will slowly get bigger and your drives to work will become more stressful as your mind plays tricks on you. Has it just got bigger? No, no, it’s still the same as when I set off, no, no it is defiantly moving, arrggghhhhhhh it’s going to fall in on me arggghhhhh.

Maybe it’s just me, I am a bit of a worrier

Its done for. Insurance is normally around £75, doesn’t usually do for your no claims.