In reply to ralphio:
A few years ago we opted out from the mainstream high street insurers and had an appraisal done and a specific policy chosen. The driver for this was that we felt (rightly) that the standard contents insurance level was inadequate. The new policy was the same price as the old. Bikes are listed specifically. A few years in we were burgled - they were only in the house for about 10 minutes and my wife disturbed them when she turned into the drive. They went straight up to where they thought my wife's treasure would be and took the lot. They didn't even look in the garage. they were doing their Christmas shopping.
The insurer sent a Claims Assessor round. We had valuations, photographs etc and documented nearly everything. we were asked for a valuation - we have it our best shot and off it all went to a specialist valuer, who uplifted it by about 25%.
In contrast - I was involved in a hit and run. The police traced the driver. My claim against their insurer was settled easily for physical injury - it seems that there is a schedule of rates for injuries. As far as the bike was concerned - it was a hand-built, stainless steel, Dura-ace lovely-thing. Pedals, bars, stem, wheels, rear derailleur, shifters etc all stuffed. They dragged it out for almost a year - claiming that we were seeking 'betterment' - although how replacing Dura-ace with Dura-ace was 'betterment' was not revealed. I think they (Zurich) thought a bike cost £300 from Halfords. Still, there was another bike and I just dug my heels in.
So - go reputable. Take photos. High street name probably not the best.