A bit of an update. I ended up selecting a pair of Focal Aria 906b speakers after a local dealer kindly allowed me to try them out alongside a Dynaudio pair with my 8200 amp. They are simply phenomenal with both the 8200 and that much better with the 8900.Again, thanks. I'm looking into a pair of Totem speakers, either the Sky or Signature One: both have slightly better sensitivity than the 686s:
The B&Ws are rated at 84 dB (2,83 V/1 m); The Totem Sky are rated at 87 dB/W/m - as are the Signature Ones. I have a family member who has been selling high-end audio equipment for decades to people with a lot of money to spend - he recommends these as the best in their price range, partly as they use Dynaudio (Made in Denmark) bass drivers that have been used in many reference speakers for over 30 years. Will see what I can come up with.