"Mark Goodge" wrote
When most people ask for a valuation, what they most
commonly need it for is for insurance purposes. And
in that case, the value that matters is what it would
cost to replace it, not what you would get if you sold it.

Ahem - why not hang around outside a jeweller and offer
someone trying to sell one, a quid more than the jeweller offered!

If a jeweller could get one for £X then your
"cost to replace" could be only just over £X...