Super cheeky of them to falsely claim that they are extending the benefits of credit spend and free postage to the entire inventory, when it has always been the case (I have plenty of proof of this, having ordered various non-beauty items using my credit and got the free postage).
I am so miffed about the whole thing that I might email and say I'm reporting them to the Advertising Standards Authority as this is a pretty flagrant misrepresentation in a commercial email.
All in all I think I'll cancel my subscription. £60 a year for effectively free postage is insane. Space NK and Sephora offer free delivery for £10 a year. I have to wonder what the marketing team there are up to - pretty amateur behaviour.