Fairy Platinum All in One Lemon Dishwasher Tablets now only £5 on rollback (were £13). Theses are available in store and online.
Personally, these are my preferred dishwasher tablet - these seem to perform better than the Finish Quantum in my opinion. I'm more than happy to pay 12.5p each for these top of the range Fairy tablets. Not quite sure who would buy the smaller 20 pack (from Asda) at the moment, as they are currently priced at £7 (35p per tablet) - almost 3 times the price!!
It's not included in the original post or description, but this looks like it's for the 40 pack.