It doesn't cover drinks or deals (buffet etc.) but pretty cool all the same. Apparently some branches are making restrictions on times and days, as well as other exclusions from the menu. Still saved over a tenner in there last week so I can't complain.
Since you only get to use it once, it's always worth taking a screen shot and printing a few more off
There's also meant to be some Tesco Clubcard Deals offer where you can get 75% off at Pizza Hut.
50% off at Pizza Hut 
