It gives you 15% off and me 15% off which if it works on top of the 20% is good but I don’t know how to check. I bought DH some shoes and lots of the matches in bottles as presents! And managed not to buy a ceramic sardine I really liked 
trouva.mention-me.com/me/referee/registerko/37729802/160350548/em/01b24a6a65370833687f074b9d2e8c4383e26fe3/fe/cw?epr=1