  A refined expression for the Faddeev-Popov determinant is derived for gauge
theories quantised around a reducible classical solution. We apply this result
to Chern-Simons perturbation theory on compact spacetime 3-manifolds with
quantisation around an arbitrary flat gauge field isolated up to gauge
transformations, pointing out that previous results on the finiteness and
formal metric-independence of perturbative expansions of the partition function
continue to hold.
