I have experience with Kef R7 (not meta version). It sounded wery good paired with Rega and Audia Flight amp. Audiolab 8300 was not so good pairing. So I think some good Rega Brio or Rega Elex or Elicit (depending on the budget) will be matching well. Similar new line of Arcam A amplifiers like A5, A15, A25 will be sounding very good with Kef LS50. Kef speakers need amp with power and control. And LS50 are excellent speakers. BR. Juraj