  We present a revised characterisation of the previously discovered transiting
planet systems HATS-34 and HATS-46. We make use of the newly available
space-based light curves from the NASA TESS mission and high-precision parallax
and absolute photometry measurements from the ESA Gaia mission to determine the
mass and radius of the planets and host stars with dramatically increased
precision and accuracy compared to published values, with the uncertainties in
some parameters reduced by as much as a factor of seven. Using an isochrone
based fit, for HATS-34 we measure a revised host star mass and radius of
$0.952_{-0.02}^{+0.04}M_S$ and of $0.9381\pm0.0080R_S$, respectively, and a
revised mass and radius for the transiting planet of $0.951\pm0.050 M_J$ and
$1.282 \pm0.064 R_J$ respectively. Similarly, for HATS-46 we measure a revised
mass and radius for the host star of $0.869\pm0.023M_S$, and $0.894\pm0.010
R_S$, respectively, and a revised mass and radius for the planet of $0.158
\pm0.042 M_J$, and $0.951 \pm 0.029 R_J$, respectively. The uncertainties that
we determine on the stellar and planetary masses and radii are also
substantially lower than re-determinations that incorporate the Gaia results
without performing a full re-analysis of the light curves and other
observational data. We argue that, in light of Gaia and TESS, a full
re-analysis of previously discovered transiting planets is warranted.
