They know the value of the item and are hoping for a bargain?

If you agree on price just add a "buy it now" for that price and complete through ebay.

Whats a second hand Hope XC rear hub worth then?

£50 if in good nick.

Stif were selling them off new for £72 the other week

If the offer is around what you are expecting then take it, it saves you the final fee from ebay and also charges from Paypal if you use them 😉

If he's giving you a Nigerian cheque and asks to send the overpayment in cash to a friend, beware!

I was offered 40.00 plus P&P but will also miss out on the fun of Ebay too.

I've never seen "Ebay" and "fun" in the same sentence before 😯

If your happy with £40 take it if you want more then stick with the auction, but beware you might not get £40 if only a few decide to bid.

Ive bought and sold loads outside auctions. Rule is keep the auction running until the item is collected.

I'd let it run, the person that offered £40 is still likely to put their bid in during the closing minutes, unless the price has already exceeded that.