Has anyone found any decent stories similar in tone to the Son of Suns trilogy but where Darth Vader recognises that Leia is his daughter while she has been captured and tries to turn her to the Dark Side?

I'm not particularly fussed with anything else about the story; I just like the plot bunny and wonder if it's been done well before.

 

https://www.fanfiction.net/s/2369737/1/Heart-of-Darkness
I can't attest to Heart of Darkness' quality, but it's a fairly popular story that fits within your search parameters. I read it about half way through a few years ago, and I didn't think that it was too objectionable. It isn't as good as Son of Suns, but hey, what fic is?

 

+1 for Heart of Darkness. It's a very guilty pleasure story but a very solid one. Would recommend reading it through, even though the last few chapters are a bit strange.