Who is responsible to arrange structural repairs?

I bought a property on a leasehold agreement and the freeholder arranges all necessary building insurance cover.

I have been told by the freeholder that, despite a structural repair needs doing and this is deemed covered by the buildings insurance, I, as leaseholder, must arrange and pay for all repairs before any insurance claim can be put in.

As this is a structural repair, and covered by the buildings insurance that I am paying for through the freeholder, I would have thought that the freeholder should be responsible for the upkeep of the buildings structure.

Also, with regards to any excess, surely it would be the policy holder that pays this (as this should be part of the service charge and ground rent payable annually) as it is their responsibility for the upkeep of external issues.