above n can be done with first-reference-note-number in CSL, no need for the cross-referencing function. This is hard with the editor, though, because that variable doesn't exist and so output doesn't preview. You can e.g. look at AGLC for an example, though:
https://github.com/citation-style-language/styles/blob/master/australian-guide-to-legal-citation.csl#L658

Hi @damnation - wow, amazing! Thank you so much! That comes through perfectly for repeated citations. And thank you @adamsmith for linking the AGLC (that is the citation style I usually use :) ).

Would it be possible to edit it slightly? I actually made a mistake in my earlier post when I referenced "above n" - the citation style actually requires it be "n. [FN#] above". So, for example, "n. 3 above" would be used to refer to the same source that was used in footnote number 3.

There's also another glitch in the style, which is that it keeps saying "at". For example, it will write "N. Craik, n. above 27, at p. 23." but it should instead just say ""N. Craik, n. above 27, p. 23." - no "at"!

Apart from that it's perfect, though - thank you so much! You've saved me so much time and pain!

Hi there,

Thanks again for your help :)

The style doesn't seem to have changed from the earlier update you gave it - subsequent citations are still coming up as "above [FN#]", rather than "n. [FN#] above". I've refreshed the citations a few times, and even deleted TEL from my citation styles and re-downloaded it from your link, but it's coming up the same as the first update you created.

That's great. Thank you so, so much!