Radio Power Connection

From a car electrics numpty - has anyone fitted a PURE 300DI DAB radio into an Impreza? Ours is a 2010 WRX-s fitted with a standard Subaru/Clarion audio 6-disc changer. My problem is finding adaptors to link between the car's loom and the radio that connect with the loom supplied by PURE. I've wasted money on two Autoleads harnesses from Halfords already, both marked Subaru fitment. These PURE products are usually fitted by the supplier, normally Halfords, but as I've bought this one independently I doubt that they would offer free advice. The supplied loom is on the bottom right of the attached picture. Any thoughts from anyone?