I get the feeling that the early issue Palitoy ones will be fine judging from his previous ebay listings, it's just the price and condition that might be an eye opener (although maybe these are his best ones?).
It's true though that it isn't an auction site so to sell things on here you really need to put pictures and prices up otherwise you may as well go to ebay and suffer the fees. It doesn't take much effort to research the price and with someone who has been selling them for years I'm pretty sure he would know the current market value and is just trying to see what people are prepared to pay. Again, may as well stick it ebay for 99p and see where it ends if you want to do this.
If it helps anyone though I was offered Toy Hunter Jordan's set of 11 (first 12 with no Luke), last year for 10K. They were in pretty good condition and that should give people an idea of how much they were back then. Prices seem to have stabilized for these first 12 since then judging by ebay and auction prices realised.
Ian