Hi, I have found a British company named INTASURE who offer very good cover for buildings and contents, it is available to both Expats and Holiday home owners alike.
They were the only Insurer that I could find that offered cover for long lets and accidental damage by owners and tenants, also the property is covered when not in use for long periods.
When I mentioned this to another insurer the lady advised me to "bite their hand off" as no other insurer offers accidental damage caused by tenants
When asking for a quote remember that the cost will be the same for any amount for upto £16,000 contents insured and then it increases per thousand.
http://www.intasure.com/?introducer=202856
Hope its of use.
captainm