All blocks of apartments have ( or should have ) a joint insurance policy to cover occasions like this. It is not dependent upon the individual tenant or leaseholder then. I am making assumptions for your situation but this is the norm for leasehold flats. It’s unlikely to be a freehold but, if it is, then the freeholder will presumably get insurance to cover all units. When you signed for your tenancy, some paperwork should have been presented to you which would say whose liabilty it was for damage insurance.
