  The rapid progress of hole spin qubits in group IV semiconductors has been
driven by their potential for scalability. This is owed to the compatibility
with industrial manufacturing standards, as well as the ease of operation and
addressability via all-electric drives. However, owing to a strong spin-orbit
interaction, these systems present variability and anisotropy in key qubit
control parameters such as the Land\'e $g-$factor, requiring careful
characterisation for reliable qubit operation. Here, we experimentally
investigate a hole double quantum dot in silicon by carrying out spin readout
with gate-based reflectometry. We show that characteristic features in the
reflected phase signal arising from magneto-spectroscopy convey information on
site-dependent $g-$factors in the two dots. Using analytical modeling, we
extract the physical parameters of our system and, through numerical
calculations, we extend the results to point out the prospect of conveniently
extracting information about the local $g-$factors from reflectometry
measurements.
