@Tanjamuse - create a boilerplate note in Evernote with the Header you want and perhaps a footer to separate your custom Comment from any regular Comment. Call it it something like Calibre Comment and make it a favourite.
Now instead of pasting the Note Link into your calibre Custom comment, paste it into the boilerplate, and then copy & paste that in its entirety to the calibre custom comment.
In the attachment the green is the EN Link, the rest is the boilerplate.
BR
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