One of the emails (for something else) was "What's the reserve price for this item?" So I told him: "£40". He comes back with an email: "I'll give you £40 for it right now"

Er, no. The reserve price is the absolute minimum that I'm prepared to accept for the item. I'd like to get more (they're £130 new). I can wait -- the item's not particularly big, and I'm not in a hurry for the cash.