Hi there - this is an interesting one. Knowing something about insurance in the Uk, I feel this is something to investigate further. For anyone buying an apartment, you should not really be able to buy buildings insurance just for a single apartment as this is a "rebuilding" cover (ie. covers you to reinstate your apartment) and you would not be able to rebuild just one apartment in the event of a fire for instance (if the rest is uninsured). I have heard of some insurers offering buildings cover on their own for single apartments but they really shouldn't. Normally in the UK, blocks of apartments or flats are insured for buildings collectively by the management company and then recharged to the owners or tenants. Not sure what Corvera are planning to do hear?
For houses on the complex or for contents covers - these are available online, I know a company, Towergate who does contents covers for holiday homes, etc www.towergateholidayhomes.co.uk
May be worth checking with Corvera regarding insurance for the apartment blocks?