It's strange that you talk about going either HE or British mini-monitors, which is what I did. Objectively, it seems that the two approaches to sound are very different from one another, but I had very little trouble making the transition from a Naim/Spendor type of sound to SETs and high-efficiency speakers. I know from going back and forth between the two sounds that I could easily pick one or the other to live with for the rest of my life, which is a rare thing in audio, with all of these people talking about accuracy and fidelity and one true sound. I believe that many types of sound are enjoyable, even if they depart significantly from neutrality.
The classic BBC monitor seems to be disappearing somewhat. Sure, Harbeth is selling speakers as fast as they can make them, and models such as the Monitor 40 and Monitor 20 are rare birds in the US since there's a long waiting list for them. But Spendor seems to be struggling a lot lately, and they do seem to be phasing out their Classic Line in favor of their new line of tall, slim floorstanders that to my ears lack some of that famous midrange magic. The prices in the Classic line are skyrocketing to the point where I doubt they're selling very many anymore. Spendor SP100s are now selling for $6995 a pair, which is insane. When I bought mine in 1998, they retailed for $3450, but I got a special deal because they were a review pair. I paid just $2400. At $7K, the SP100 is no longer competitive. It used to be said that the SP100s were the second greatest British speaker, next to Quad ESLs. But the Quads were much more expensive back then. Now, the prices are getting pretty close.
The prices of Harbeths are getting kind of crazy, too. The newest version of the Compact 7, which just came out, is $3000 per pair. Just a couple of years ago they were $1995, and were a bargain. Now, the little "shoebox-sized" HL-P3 is $2000. And I remember the Monitor 40s being around $6000 per pair when I first heard of them three or four years ago. Now they're $10,000. Yes, they're one of my very favorite speakers in the world, but at $6K I had a chance of owning a pair one day. Not now.