I use eBay very infrequently and have never come across this before, so not sure what the done thing is!
Recently sold a few things on there, nothing expensive, mostly around £5. Made sure it said that I didn't accept returns as frankly not worth the time and effort for the amount I was selling for. One of the buyers has messaged to ask if they can return one of the items. I know I don't have to, but is there any eBay etiquette around this? Am I likely to get a negative review etc? And if I should stick to my guns, can anyone suggest an appropriate polite response?!