  We present an analysis of the exclusive semileptonic decay $B\to D^\ast
\ell\bar\nu_\ell$ based on the Belle and Belle II data made public in 2023,
combined with recent lattice-QCD calculations of the hadronic transition form
factors by FNAL/MILC, HPQCD and JLQCD. We also consider a new combination of
the Belle and Belle II data sets by HFLAV. The analysis is based on the
form-factor parameterisation by Boyd-Grinstein-Lebed (BGL), using Bayesian and
frequentist statistics, for which we discuss novel strategies. We compare the
results of an analysis where the BGL parameterisation is fit only to the
lattice data with those from a simultaneous fit to lattice and experiment, and
discuss the resulting predictions for the CKM-matrix element $V_{cb}$, as well
as other phenomenological observables, such as $R^{\tau/\mu}(D^\ast)$. We find
tensions when comparing analyses based on different combinations of
experimental or theoretical input, requiring the introduction of a systematic
error for some of our results.
