That sounds like a one-use one. Though you didn’t get an automatic one, so Customer Care may have given you a stand-in.
You are now the Anniversary discount guinea pig. 
You must report back on everything you discover, and let us know how you get on. 
I do believe @Ian_Chimp that you are taking the proverbial piss! They’ve probably disabled yours on purpose 
Moi? How very dare you.
I have read all the info, and now I’m pressing all the buttons - you have to test these things out.
I have only ever had one on here but looking just now it wasn’t set to primary (as I don’t think that was a thing when I set it) . It is now primary and I shall wait and see.
I noticed that the other day. I’ve set it as primary now but I wonder if that was why I didn’t get the discount email.
I had mine set to primary, and I got nada. 
No idea then 
Maybe you’re on their naughty list and you don’t get one @Ian_Chimp
It’s all a bit confused at the moment. Hopefully they will sort it out with time. I’ll let you all know how I get on over the weekend
Things that we now know:
What we still don’t know:
Anything else?
Nothing else I can think of!
Can I have 2 Birthdays too please? When would the queen get her Birthday discount I wonder? 
I’m in a weird mood today, feel free to ignore my weirdness!
Is the one you’ve been given 40% off £50+ like the Unlimited birthday one?
Did we learn any more about this? My anniversary list is piling up ready for next month!
Oh yes! You just reminded me! I emailed customer care and they replied with a code for 40%off but when I tried to use it, it only gave me 20% off which isn’t very helpful when I’ve already got the 25% unlimited discount 
I emailed them back and they very quickly got back to me with a correct code which has now worked 
In short - email them and you should get given a code 
Were there any spending minimums? 20% off £40+ and 40% off £50+?
So it seems there maybe be two tiers to the anniversary discount. Split on standard/Unlimited maybe? But then how do new people get the good stuff? 
And still no Anniversary email for me yet. 5 days to go.
No minimum spending required. I was told the code would last 28 days but I’m not that patient and I’ve already used it!
I just spoke to customer service about it and they have provided a 30% code even though I mentioned I’m unlimited. might be worth me asking again. It seems the new site is still providing teething problems
It’s worth asking again. The first one they sent me was 20% off, when I emailed back and said I thought it was supposed to be 40% off, they sent me a new one. Unless they are changing the discount amounts? Definitely worth asking. Hope you get it sorted and Happy Anniversary! 
So sending an email saying I belive it should be a 40% discount worked and they replied very quickly,so not sure why I was given a 30% code originally. So order placed and has been delivered already.
Hoping the OH will do a fashion show for me at the weekend 
Yay! Good news have a lovely weekend x
Nothing has arrived for me automatically, so just sent an email to customer care chasing as its our anniversary next week (with a hotel and lots of fun planned!)
Hopefully they get back with a 40% discount code!
If they don’t get back to you in time hop on to livechat, they should get you one in a few minutes 