Hi Dave & Dee,
It actually sounds as though your site is taking its responsibilities seriously. I have never heard of any other sites that do cover under their own insurance. If any one else knows of any that do, perhaps it would make a useful topic on the forum.
From what I have previously found, the majority of storage sites try to operate a policy of caravans and content stored at owners risk clauses. This is very similar to the 'Cars parked at owners risk' that used to be seen in most car parks, but now have in many cases been removed.
Any private person or company one who charges to allow other persons to store property is running a business, and that carries a number of responsibilities that are not necessarily obvious. If you simply provide a space with no added security measures, then you might get away with only renting space, But as soon as any form of security is added, then you are also providing a service designed to prevent unauthorised access or removal of a clients property, and that brings a different set of responsibilities and liabilities.
Car parks that are simply pay and display with no barriers, offer no added security, and thus in most cases they are simply renting space, but as soon as you offer a barrier to restrict entry or exit, you have added a security element. If that security is breached and a clients property is removed or damaged, then your service has failed, and site owner has some liability.
In the case of a 'secure' caravan storage compound, the emphasis is on security which should provide protection against unauthorised access to the compound, and prevent the loss or damage to clients property. If the security fails and loss or damage to property ensues, the site owner is responsible. They have failed in part of their service provision area which is security.
As most storage sites are privately owned and are on private property, I am sure that many casual site operators are not aware of their responsibilities. Consider a site where a fenced compound is secured by some form of lock or access restriction that limits pedestrian access. The site is clearly designed to keep unauthorised persons out, and by deduction, anyone able to gain entry through the proper security channels must be authorised. It is the sites owners responsibility to choose who to 'Authorise' or not. they are therefore responsible for the actions of anyone who is given authorisation to enter the compound.
If the site owner believes that someone who applies for access is going to cause damage, or not follow the owners guidance on how to perform any activity within the compound, the owner has the right to refuse access. By the same token anyone the owner grants access must be considered a suitable person by the owner. It follows that the owner tacitly approves of any action taken by anyone inside the compound. If that action causes damage to other clients property, then by the previous logic, the owner of the site is responsible for their actions, and liable.
It also follows that if some low life gains access to the compound by any means, the damage they may cause is the site owners responsibility, and claims should be made against the site. The site owner has failed to prevent an unauthorised access, so security is breached. It is then up to the site owner to pursue the offender to obtain redress through the proper channels.
That is the prime business risk that sites must carry insurance for.
In any case, the site owner should carry indemnity insurance against loss or damage to clients property whilst on or in their compound.
The car parks were I believe successfully challenged on the basis that that site owners cannot absolve them selves of all responsibility if a security service they are providing is breeched.
Caravan storage site owners should take note.