Look back at the listing for the item. What does the location say? If it says a UK location , the item goes back to the UK, Not China.
I presume they accept Returns, this also is written on the listing. Open a return for a change of mind reason, and you'll need to pay for the return postage for a change of mind reason , to return the item to the UK.
One tip, I had this recently, and the seller provided a Chinese address, this is wrong. If this happens contact eBay Customer Services, they will either provide the correct address for you to return the item to, or as in my case, they'll make a discretionary refund for you, and you may not need to post it back.
This is the easiest and quickest way to contact eBay Customer Services, for a Call Back option.
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Lines open between 8 a.m. to 10 p.m. on weekdays.
9 a.m. to 6 p.m. on weekends.
I recommend contacting CS very first thing in the morning, when the lines first open, as there's more chance of Dublin answering.
@jimthompn