  We consider SU(3)-equivariant dimensional reduction of Yang-Mills theory over
certain cyclic orbifolds of the 5-sphere which are Sasaki-Einstein manifolds.
We obtain new quiver gauge theories extending those induced via reduction over
the leaf spaces of the characteristic foliation of the Sasaki-Einstein
structure, which are projective planes. We describe the Higgs branches of these
quiver gauge theories as moduli spaces of spherically symmetric instantons
which are SU(3)-equivariant solutions to the Hermitian Yang-Mills equations on
the associated Calabi-Yau cones, and further compare them to moduli spaces of
translationally-invariant instantons on the cones. We provide an explicit
unified construction of these moduli spaces as K\"ahler quotients and show that
they have the same cyclic orbifold singularities as the cones over the lens
5-spaces.
