If a buyer has decided he doesn't want the item, do I have to pay for him returning it?

[spicemonster]

This is the first time I've ever sold anything so I've probably done it all wrong so would appreciate some advice. I sold a changing bag which sells for 50 quid new for just under a tenner. The buyer has now said he wants to return it as there is a mark on it (it is tiny but in retrospect I should have mentioned it). I can't be bothered to have a big fight with him but do I have to pay for him to return it? He says the item is not as described but I said it was in good condition (which it is), I didn't say it was immaculate or as new or anything like that.

What is the best thing to do please? Thanks

[spicemonster]

I don't think he wants the bag. He's a bit precious it seems to me - he bought this bag as a replacement for his because it got some milk spilled in it! I would rather him keep it - can't honestly be arsed to relist it and post it all over again. Shall I offer to pay 1/2 the cost of postage? Does that seem reasonable?