To be quite honest, if you are selling fairly bulky yet delicate items such as antique clocks, yes, I would be inclined to sell them as pick up only & I would be inclined to try other sites, not just ebay.
You're selling an expensive item there & my feeling is most buyers would be interested in it for its age/design and not only for its ability to tell the time.
It is possible that it was working at your place but after getting a bit of a rattle around during delivery, it has stopped.
My main worry for you with selling on ebay is that with second hand items, they can stop working at any time, it isn't your fault and you may one day get a buyer who has a clock that works for a week or so but then expects a refund down the track if anything happens. I wouldn't trust ebay not to grant them their money back, even though you should not have to be providing a guarantee.
