If you own, or are looking to insure a commercial building, you will find a great variety in the prices, or premiums, you will get from different insurers for the same type of risk.
As with all financial services, it pays to look around. There are a lot of consumer based sites around that all say the same thing. Do not, whatever you do, buy a financial service or product from one single company. Without a shadow of a doubt, the one thing with banking, insurance, mortgages etc is that you will in the vast majority of cases always get different prices. It is just the way of the world in this day and age.
Commercial insurance companies love, and survive, through customers not looking around. If the law were changed and you were not allowed to insure with the same company for more than one year running, you would find that prices would plummet. You would get the super introductory, new business super deals year in year out.
For unoccupied building insurance, you will need to be even more careful. Most insurers will only provide you with five covers. Fire, lightning, explosion, aircraft and property owners liability for empty buildings. They have years and years of statistics which show that they do not make money on empty building cover, unless they restrict the cover and charge higher prices.
There is a silver lining though, that is that certain insurers do know how to make money at this type of business and are prepared to offer better insurance cover at better prices as a result of this knowledge of the market.
So, wider cover is available, what you do need to do though is to look around and see what options there are. As ever, speak to a business insurance broker and see what availability there is for the wider cover.