  An analysis of various decay processes is performed using the two mixing
angle description of the $\eta$-$\eta^\prime$ system, incorporating the link to
the gluonic sector through anomalies. The agreement is excellent. For
comparison with previous works, our results are expressed both in the
``octet-singlet'' and in the ``quark-flavour'' basis. It turns out that at the
present experimental accuracy, the two angles are significantly different in
the former, but not in the latter basis. The implications of our analysis for
the Large $N_c$ $\chi$PT predictions are also discussed.
