  The binary system GG Tau A is observed to have a circumbinary disc with a
dust ring located further out than expected, assuming a co-planar disc and a
corresponding semi-major axis of 34 AU. Given the binary separation, this large
cavity can be explained by relaxing the assumption of a co-planar disc and
instead fit the observations with a mis-aligned circumbinary disc around an
eccentric binary with a wider semi-major axis of 60 AU, consistent with fitting
the proper motion data for the system. We run SPH simulations to check this
possibility and indeed we find that a misalignment angle of 30 degrees and a
binary eccentricity of 0.45 fit both the astrometric data and the disc cavity.
However, such configuration could in principle be unstable to polar, rather
that planar alignment. We investigate the secular evolution of this
configuration and show that it is indeed stable throughout the disc lifetime.
