That really takes chutzpa. But it’s an odd choice for the seller, who would seem to have acknowledged the buyer’s complaint by refunding his money. (That’s “seem” — it need not be the case at all.)
On the one hand, of course, UK libel law is a lot more plaintiff-friendly than that in the U.S. On the other hand, under the English Rule for attorneys’ fees, the loser pays.
An interesting subtext in the story is that eBay doesn’t give buyers the opportunity to respond to negative feedback from buyers, so the seller — who evidently does a lot of eBay business — evidently felt that this was the only way he could “respond.”
On the other hand, will anyone ever buy from Joel Jones — “onsalexuk” on eBay — the guy who will sue you for negative feedback — again?