Instructions:Have just received a text message for BOGOF Pizza Hut for delivery only. Works online, I've just checked. I assume they are trying match what Dominos are doing.
Choose your pizza and add it to the basket, then enter the code in the box for promotional codes. It will then take you to another screen where you can choose your free pizza. Apparently it excludes Pizza Mia and Calzone and all pizzas have to be from the full price menu.
Anyway, happy scoffing