Mixed experiences with The Vintage Watch Shop (Ebay)

This one's a bit more complicated. I first made a sale to Chris at The Vintage Watch Shop via Ebay. He mostly sells and buys on Gumtree (he's located in Bingley, West Yorkshire). He was unhappy with the watch, accused me of hyping it up, and then said that it had stopped working. It had run fine for days on my end, but I accepted his account and gave him a full refund.

About a month later, I purchased a watch from him on Gumtree. When I sent it to my watch guy, he pointed out a problem with it, serious enough to require repair and just more than I wanted to take on at the time. I wrote Chris and asked to return it for a refund. He refused, claiming that the watch "was still fine and ran fine" and that "you bought it a few weeks ago and now it's been opened up." I explained that I don't control my watchmaker's bench, and a wait time of a few weeks is pretty normal. No dice.

I couldn't help but notice the contrast between how I handled his issue and how he handled mine. I certainly wouldn't go so far as to call him dishonest, and he was polite throughout. But on balance, I don't think I would buy from him or sell to him again, and anyone who considers either a sale or purchase should go in forewarned.