A friend bought me a necklace as a present but gave me the receipt saying I could take it back if it didn't suit me. It doesn't and I really want to but can't find the receipt anymore. Is my only alternative to go back to the friend and ask her to find proof of purchase or do you think there is any chance the shop would exchange it anyway? I think it's obvious it came from the shop as it's in a lovely box, etc, etc. Is the shop bound by law to only exchange on proof of purchase or do you think I could be lucky with a nice person behind the till?