Hi Lew,
I have never heard any Fyne speakers, so I cannot help you there. However, I do own Graham LS5/5 speakers which I compared carefully to the Harbeth 40.3xd. I'd be very interested in your thoughts about the two since you own them both. Harbeth just came out with the 40.5, so that might be an improvement. I expect it would be evolution, not revolution.
Like you, I never could warm up to the Focal Scala Utopia EVOs. Just too bright and fatiguing. After a number of years with the Grahams I feel like I know what they do well and where they could be improved. With that in mind, I have started exploring my own upgrade. Unfortunately, the Clarisys Studio+ and Stenheim 5se that I think also sound as musical and natural as the Grahams, while having greater resolution, dynamics and better sound staging are a lot more expensive.
Is there any reason why you chose the Fyne's as a possible upgrade and did you consider any other speakers?