Modal pop-up issue when using more than one pop-up on a page

Hi, I have successfully used the tutorial here https://theadminbar.com/css-only-modal-with-generateblocks/ to set up a CSS pop-up box on a draft page (see below in Private Info). I have then attempted to set up a second pop-up on the same page using the same method but with slightly different html anchors, this has been successful except I cannot get the 'close' button to show on the second pop-up as changing the html anchors for it doesn't work for me. I can (and have) created a button with a link to the previous page instead, but would still like to be able to use the 'close' button if it is a straight forward fix. Or at least have that option.

If you visit the draft page below the two pop-ups are initiated by clicking on the links under'Useful Links' in the middle of the page. The first pop-up shows the close button, the second pop-up doesn't.

Can you help please?

Thanks,
Nicola