Y4Food lists all online takeaway sites and provides links to the pages that are near you.

There are some easter eggs hidden throughout the site leading to a page with current deal codes.

The offers page can be found here:
Y4News | Y4Food Offers

There are currently some pretty useful discounts and are updated regularly so always current.

The front page of the site is here: Find Local Online Takeaway... | Y4Food | Take Away Online Delivery Menus | Order Food | Pay by card | Eat and Enjoy!