A more common and tested option would be the
Nuforce Icon 2. It's a DAC, headphone amp, and can power smaller passive speakers, for 319£ on
Amazon. The nominal output power of the Icon 2 is 24 Watts per channel @4 ohm, which should work considering Wharfedale says suitable amplifier power for your speakers is 20-100W (
source), and their nominal impedance is 6 ohm. Do note that I don't have real life experience of the products in question, I'm just reading specs.