Dear Notec,
I have the LED LE III & Harbeth Compact 7ES-3. I have heard Proac's, but not the D Two's. I have also had the pleasure of hearing the Supernait. I have not had a lot of time listening to my LFD LE III with my Harbeth's, but enough now to know it's a special mix, and this is no bluster, or "I want it to sound as good as reviews say because I own one at last." I listen to 85% classical (right now listening to a Telarc recording of Moussorgzy "Night on Bald Mountain" and I'm getting chills from how good it sounds), 15% Jazz and some acoustic and some Steely Dan type pop when the mood strikes. Let's just say I'm pleased with the sound on all genres - and that's coming from one who acclimated to the sound of the alluring tube amplifiers - in my case a tube amplifier that had the manufacturers latest updates and with a tube roll into Mullards and RCA backplates. As we know about audio equipment likes: it's all subjective. I don't feel you can go wrong with any of the fine components you mentioned, but IMO the Harbeth's and LFD really do shine (at least in my experience), as long as your source material is also really good, and IMO the lack of very well engineered recorded source material is ultimately what holds back many fine systems from being good and not great. Best of luck chasing the glorious alchemy of electronics and sound.