I've just noticed I got an email this morning from Thornton's offering half price boxes of 780g Continental chocolates for £9.99 (normally £19.99).
The email says "today only" meaning Thursday so whether this will still be on come the morning or not I don't know.
I clicked on the link in the email and it automatically puts the code XE9M in the voucher box at checkout but I'm not sure whether the code does anything or not as it seems to stay the same price even if I remove it.
Standard delivery is £3.95 for one box but is free for 3 or more boxes if using code PRC9
15% Quidco is also available and on the Quidco it mentions you can add free 400g box of Continentals by following the below instructions. Not 100% sure if this can be used alongside the free delivery though so you might have to choose either / or.
*Spend £15, excluding delivery and you'll receive a free box of Continental Chocolates (400g), worth £12. Follow the instructions below to recieve this offer: 1) Add items you wish to purchase to your shopping basket 2) Enter the code 'XQFC' to the code box 3) Return to continue shopping 4) Go to product search and enter '5810' (the chocolates will now appear) 5) Return to basket and make sure only one continental box has been added. If two have been added, remove one and the remaining box will be your free gift.