I went through a similar situation myself, except I was coming from a pair of Proac D2 (which may have a similar sonic signature to Harbeths, I can't say but maybe others can). A good pair of Proacs was always my "holy grail" and I finally got them, and they were better than anything else I'd ever owned. Living with them a while I noticed that they were very musical, but also warm and not entirely transparent. That sense of the music coming from a wooden box never left me. My listening room is also near-field, about 5-6 feet listening distance, and my budget was $3000 and I wanted more transparency, more clarity, a more dynamic sound.
I researched many of the same names mentioned on the thread so far - and there are some fantastic recommendations here - but ended up going in a different direction and trying a pair of used Wilson Benesch Arcs, with their steel & carbon fiber cabinets. I wanted to see what happens to the sound when you remove the wooden cabinet from the equation, and the answer is what I was looking for. In fact, I liked that effect, of removing the wooden box, so much that I then bought a pair of extruded-aluminum cabinet BMC Purevox for our larger living room (would have bought bigger Wilson Benesch but they too rarely come up used and I can't afford new). The Arcs are clear, transparent, dynamic, and very airy - very much a you're-in-the-studio-with-them or in-the-concert-hall type of sound. And there happens to be a pair available here now, pre-owned and mint, for under $3K.
Only warning is that transparency comes at a price. If you listen to a lot of '80s rock, especially badly-recorded content like so many of Pat Benatar's albums, Bryan Adams, hair-metal, etc., the Arcs don't hide or protect you from that like warmer, more colored speakers will. If all I were going to listen to forever was Bryan Adams' "Reckless" album, I'd stick with the Proacs. But on anything recorded well, the Arcs are in a different league. But there's no coloration to protect you from poorly-recorded material. Hope this helps.