Wallet on iPad mini

I tried to add a Boots Loyalty Card to my iPad wallet, I clicked on ‘add to Apple Wallet’. I then realised that I don’t have iPad Wallet on my iPad mini. So I went to my iPhone and tried to add the same card to Apple Wallet on my iPhone. It said, ‘ you can only have this card registered on one device at a time’ or words to that effect. I cannot delete the Boots Loyalty Card from a non-existent wallet! What can I do?