My refferal codes are still not working. For some reason all my codes don’t work at all on my account. 
I gave one of my codes to my mate and it worked straight away for him. So I am befuddled.
I tried on different browsers too and get the same error.
Try mine. Type in ‘Jodie Martin’ at checkout under discount or referral code 
As far as I know, referral codes work only inside the boundaries of each store. So if you have a UK code, it works in UK store, and so on. If anyone knows more of it, please correct me. 