I agree.
IMO, what Naim should say is that they recommend using their own cables, with a minimum length of 3,5 metres - or cables which provide at least X pF and Y μH.
Based on the spec for A5, from @GadgetMan above, then using 3,5 metres of A5 these figures are:
Capacitance - 56 pF minimum
Inductance - 3.5 μH minimum