Cheapest way for me to to insure my M8 was to add it to my household policy - much cheaper than a dedicated camera policy.
My policy covers the new replacement cost of one or more items up to £5000 in value outside of the house, including on holiday abroad. As the Leica was the single most valuable item, the insurers wanted brief details ("Leica M8 camera" sufficed).
As household policies vary, it's important to check the small print carefully, to ensure that it covers everything you expect it to.