Nigel,
I agree with you, but you cannot "buck the market", as dear old Maggie said. I have been offered ?100 for my first edition, and of course I have turned it down.
If people want it, they will pay for it, especially if they want it bad enough. This first edition of Walker's Biography has sold out. Look after it guys, this is one book, that in 10 years time you could probably buy an old age pension with.