Hi David,
That seems to have worked. The card boxes have appeared and also the second address has gone. The card icons are a sensible size without the CSS you provided earlier.
I adjusted the container as you suggested above but the new checkout page is not conforming to this and is all squashed up in a narrow column. I could live with this as its all working now at least, but it would be good to give it more space if possible.
Thanks you so much for your help with this. Home stretch!
Cheers, Tim