Had a good offer on the new Signature model, but chose to go the BBC line of speakers with an other designer I admire a lot, mr Derek Hughes and his Graham Audio LS 5/9.
The Graham speakers are an endgame speaker
I lived with the Harbeth SHL5+ for more than a decade and now own the Graham LS5/9. I agree it’s wonderful, only if it’s matched with the right amp. I find Graham to sound best with a robust and dynamic amp with a propulsive quality. The LS5/9 sprung to life when driven by the Naim 282/250DR. When used with the Luxman L-590AXII music sounds lacklustre, flat and pale.
The Marten speakers are a much better match with Luxman than Naim.
I once considered the Gryphon Diablo 120 and 300 for the Marten but that didn’t happen. I don’t have experience with the Diablo 120 but reading about the dark quality of the treble, I would avoid warm or laid back speakers such as Harbeth or Graham. Nevertheless, the propulsive quality or drive of the Gryphon may suit these BBC speakers, I’m not sure.
By the way, on Graham vs Harbeth, I find Graham to be 👍👍.