Can’t get building insurance certificate from freeholder?

Hi, despite my repeated emails to my block managing agent, my freeholder is not providing the block’s building insurance certificate.

I am entitled to a copy by law. But what law? How do I identify the individuals who own the freehold (I have the company name) and their addresses in order to write to them direct?

Block managing agent writes “I assure you it is insured.” I have replied, “I want the certificate as I have the legal right to it.” The last insurance expired Jan 2024.

The freeholders bought the block specifically to add 2 extra storeys of flats on top. They have planning permission and have started some building structure investigations.

I have some ceiling cracks in my top floor flat I want the insurers to look at. The freeholders know about the cracks. Managing agents have advised me not to call in insurers but pay £600 plus vat for their own appointed surveyor.

Refundable if issues are found. Should I say I want to use my own trusted surveyor instead? Neither of these surveyors are likely to go on top of roof to inspect it as would probably need a cherrypicker.