Depends on how sharp the claims people are and what caused the crack, if it’s due to fatigue it shouldn’t be covered but if it was a crash then it should. On the not being able to move insurers thing that would likely to have been because it was a burglary claim, and I expect a big one. With some types of claims (burglary, flood and subsidence mainly) there’s less chance and insurance company are likely to take a punt on it, as there’s often an recurrence shortly afterwards.
If it’s an expensive claim, have a go why not, you can always speak to your insurer and see what difference it makes to your premium, and if you do claim and it’s not worth it, you can always pay the claim back.