There are not too many of them about and they continue to be in demand so if it really is good then it could well command that sort of price and I can see somebody paying it as well.
It must be said that there will also be bargains if you are lucky enough to find yourself in the right place at the right time but finding one for less than £350 is getting to be more and more difficult so maybe £450 is what they are going to sell for now?
The same old maxim applies - it is only worth what somebody will pay for it and if somebody will pay £450 then the price is what it is.