They had some technical issue with that code
Anyway cause of that, I just got an email:
Due to the massive popularity of the 20% off everything 24hr sale, a technical hitch took place. To make it up to you, here's a code that allows you to shop with 20% off everything, any time you like, until 18 December.
Just enter promo code APOLOGY20 at checkout
It's working for me, just got a GHD iron
for a friend for less than 100EUR