Fingers crossed for ya
They can't honestly give you less than MARKET value (can they?) ... I mean "markets" go UP as well as down ... supply n demand ... that's the insurers fault ... they probably make a good deal of money out of people anyway, because they COUNT on the fact that when you insure you're £3,000 bike, that by the time you actually make a claim, with depreciation n all that, the "market value" of the bike will have gone down to £1,500! They also need to accept that in SOME cases, such as in times of "demand outstripping supply" that the market value of a particular type of bike, may actually have risen from the "estimated value" at the time of purchase.
However, as Ashy says ... these are insurance companies
Good luck tho Laura
Pete