As in your other thread, advice will be the same; look for an amp that doubles it's power from it's 8 ohm rating to 4 ohms. (or close to double)
The impedance curve of the One's shows how hard they are to drive; The amp has to be able to drive the spkr below 4 ohms.
Rega Elicit...
105 Watts per channel into 8Ω
162 Watts per channel into 4Ω
Looks too low IMO. But the website states a Class-A driver stage, so I don't know.
Were you able to try any other amps from your dealer?