No, there is no option to output the referrer via Articles Anywhere.
You could use Sourcerer to output the referrer via PHP. But what if someone gets to that order page via a different route (direct URL or link from somewhere else...)?
What you could maybe do is search for the landingpage article in the same category as the order article.
Then you can output the link to that.
What do all those landing pages have in common?
Do they have something in the title or alias that is the same? Or is it always the article with the lowest ID in the category? Or the first in the article ordering?
What about the second idea. The idea is to look if the slug of the articles in the category are NOT order-* and NOT thank-you-* which should result in the landingpage. Or am I wrong?