Ted..... I've sat here and worked out how much all our bikes are worth using your formulae, it's bollocks 😂😂😂😂😂😂. (no, I'm not being rude to Ted for anyone that thinks I am 😁😁😁😁)
I think you have misunderstood my formula Julie it's nothing to do with valuation or potential price at auction. it's for setting a sensible reserve to attract interest.
I would also set the reserve at £5k.
Setting an unrealistic reserve tends to not end well. Setting it low can attract interest, the bargain hunters soon drop out after a few bids when the serious buyers step in.
If one has owned an old bike for a substantial period of time then clearly in place of your original purchase price then the current price of an unrestored model is used instead - my reserve guide is ideally based on a bike that has been owned for 2 years or less.
Clearly rare model versions / variant are in a market of thier own.
Auction prices are often a distortion of true value as on the one hand bidders can get carried away - then there are firestorm sales when stuff is extremely cheap amd below the normal market price as the seller is desperate or the item is out of season.
A vehicle like a house is only worth what someone is prepared to pay on the day.
I used to frequently attend car auctions both as a seller & buyer but that was decades ago.
I did buy a portrait of Joanna Lumbley once at a charity auction at Allied social club in Burton-on-Trent I outbid the only other keen buyer.
Wendy went balistic as it was lets say artistic - luckily Wendy knew the other bidder through a friend - I sold it to him the next day for a small profit that I was then made to donate to the charity on the night.