Pledged at the "elite collectors edition" and added the dlc season pass to my pledge. I redeemed that before the game came out and it's listed as dlc I own on steam so that's all fine but a second option to redeem a key has shown up in my products. (idk if it works as I haven't tried it) 

 

Did this come with my pledge and I have just bought it again by accident?  (if so i'll just give it away no need for a refund)

Yes- They added it to the pledge level later

Yes- They added it to the pledge level later

 

Ah ok cool, I must have missed that update or just completely forgot about it. 

If you don't want it you could give it me ?

Not sure if it's too late, but there was a FAQ earlier, saying that if you wanted a refund for buying a DLC key before it became part of the $150+ backer tier to shoot them an email.  Maybe they can still work something out.