My Dear Shop Manager
I was in on Monday when I bought a chamber pot for Aunt Madge and you unreasonably refused to mark the receipt to the effect that it was a gift for her and that she should exercise all my consumer rights as a third party. I let the public know about my visit in my post of 5 December 2016. As much as it irked me to do so, I still bought the pot because it was in Aunt Madge's favourite colour of pink and I could not get that colour anywhere else. I won't tell you the colour they had it in next door!
Anyway, I have looked up the law in Breaking Law by my new best friend Stephen Gold and I can get round your obstinacy. I have delivered the pot early to Aunt Madge with a card in which I have assigned my rights. So I require you to take this letter as formal notice that by my card to her dated 7 December 2016 I have assigned to Aunt Madge of 106b Acacia Avenue, Twickenham all my rights and remedies under the Consumer Rights Act 2015 and otherwise in the contract for the purchase of the pot. This means that legally she steps into my shoes although she in fact wears a size 4 court shoe and not hobnail boots.
So put that in your till and smoke it! Merry Christmas.