I have also just tried (which I believe is unconventional and probably wrong):

SpeakerLink LR Master to Left Front
SpeakerLink LR Slave to Right Front
SpeakerLink C/Sub Master to centre SL and centre set as master

With this configuration all turns on and off and volume control work with 861 as controller (I believe looking at it this is how it was before) but still not (or very little sound) through L/R on calibration but Centre OK.

Meridian..(all gone for now 😞)