In reply to Offwidth:
> Cheeky..... they go for over a hundred if in good nick.
No they really don't!
You've fallen into the classic trap of thinking that an online advertised price for certain items has any relation to actual sale prices.
They don't sell for £100 - if they actually sold for that money, you would not still find them listed for that amount on abebooks.co.uk, they'd all be sold!
I'd also be about £500 better off as I've sold seven copies in the Series in good or very good condition in the last year for £20-£40.
Online prices for things like antiques and antiquarian books only tell you what things ARE NOT selling for. Some guides do genuinely sell for hundreds (e.g. Laycock's Some Gritstone Climbs) but because they DO sell, there aren't ever any copies for sale.
Some copies of Gritstone guides listed by at least three prominent book dealers have been on abebooks for over TEN years and still haven't sold. Traditional antiquarian book dealers work on turning over as little as 10% of their stock per year so are absolutely not in any rush to sell and their prices reflect that.
Private sellers rarely have the luxury of either waiting years or, as the large online book sellers do, listing at a speculative price and then gradually reducing it over a period of weeks.
That said, something is worth as much as someone is willing to pay for it. Admittedly these days it can seem rather hit and miss and super dependent on whether some opaque algorithm puts the advert in front of enough people's phone screen. Loads of people are content to make impulse buys with doing the slightest research, so despite having a clear personal view of the intrinsic value of certain items, I'm continually surprised how much over the odds certain things sell for!
FWIW I'd feel guilty asking for much more than £15 plus postage for a copy in that condition, but some vintage Climbers' Club guides I advertised recently would have sold half a dozen times over within a morning so maybe I'm guilty of selling things for slightly too little...
Post edited at 12:01