Just received this e-mail from Iceland:
You have been specially selected for our exclusive Bonus Card Savings offer
Simply save on your Bonus Card ending ******** between 18th November and 1st December and we'll give you an extra 50% savings on top!
You can add savings in one or more transactions, they'll all count.
Your 50% reward will be loaded onto your Bonus Card on 8th December and will be valid until 31st December.
maximum of £50 bonus according to small print, probably account specific but not sure.