I've retired my LS50s to TV sound duty, running them with a Devialet 120. With the Devialet's SAM feature, the KEFs were unlistenable on movies: the bass was simply overloading anything else the speakers could do.
To resolve the problem, I picked up a $399 SVS SB-12 NSD from Amazon. Because I've been too busy and too tired to do measurements in the family room, I quickly found a recommendation from KEF that subwoofers be crossed over to the LS50s at 79 Hz and followed it, setting a 4th-order crossover to the KEFs at 79 Hz in the Devialet.
The sound is now superb for TV use, and with most listeners off-axis anyway, I think the LS50s plus a subwoofer are more or less ideal for two-channel "home theater." I will test it with music in due course.