OP we are Naim dealers and you can use any good speaker cable with banana plugs you certainly don't need to use Naim's cheapie banana plug adapters.
The reason Naim wants you to use their Cables is that the Naim amplifiers are looking for a certain amount of inductance.
We sell adapters made by Wireworld which plug into the bananna jacks of the Naim amplifier and then you plug your cables into these adapters and now you can upgrade the sound dramatically by using higher quality Wireworld speaker cables.
The Naim gear on better speaker cables will shock you how much better the sound quality can be, also in many instances you won't need these adapters at all.
Dave and Troy
Audio Doctor Naim dealers