Adrian
And most good policies do. Time is of the essence. If the crack damage is allowed to mature it will certainly get worse. Capilliary action of water coupled with a hard frost and it will be rendered irrepairable.
I think that is about right. Must have been a heck of a bang to do that much damage. I got a 6" coach bolt hit mid windscreen once at 70+ and it did a great job on it to my amazement!
Talk to them and-or read the small print. You don't have to make a claim if it isn't cost effective to do so. It is one of those rare events where you may be pleasantly suprised by their quality of service. My insurers provide a couple of clear elastoplasts to stick over any windscreen damage to keep water out until it is convenient to take it in. ISTR it takes the repair system about an hour to cure.
It is rather important to be able to see through the windscreen so I wouldn't begrudge them the £50 if it isn't repairable. Had that happen to me once too - right at driver eye level with a similar sized projectile. I was *very* pleased the windscreen held.
Regards, Martin Brown