Good lord, they're awful. Couple of quid in a charity shop, perhaps? At £600+, not a snowball in hell's chance!
Back in the early days of eBay when I actually gave a hoot or two, I used to occasionally query prices with sellers if I thought they were, shall we say, verging on the unrealistic. I soon learned to wind my neck in after a couple of worryingly unhinged and downright abusive replies.
It's definitely best just to shake your head and move on.