Re:
Think I could have answered my own question here - subject edited since forks are now for sale.
Had thought I'd have to cover costs of finding what I needed at FleeceBay prices, but it looks like I've now sourced a later disc TB fork for a reasonable price.
I'm therefore pricing in the spirit of fairness at £30 plus postage, which covers the costs of my purchase.
I think it will be order of priority running from the people who have already put in a shout for the sale, so if the earliest enquirers still want to buy they get first dibs.
Cheers!