jtx:
Be aware that applying for cards like this just to get cashback will affect your credit rating due to multiple credit searches.
You're right that they do a credit check each time you apply but it really only affects your credit rating when you get declined. It's best not apply to several credit cards, loans, bank accounts etc. in a short space of time regardless of whether you get accepted.
I'm going to wait a little bit because I just applied for a high savings current account with overdraft as well as a credit credit card at the same time.