  We further investigate the case where new physics in the form of a massive
$Z^\prime$ particle explains apparent measurements of lepton flavour
non-universality in $B \rightarrow K^{(\ast)} l^+ l^-$ decays. Hadron collider
sensitivities for direct production of such $Z^\prime$s have been previously
studied in the narrow width limit for a $\mu^+ \mu^-$ final state. Here, we
extend the analysis to sizeable decay widths and improve the sensitivity
estimate for the narrow width case. We estimate the sensitivities of the high
luminosity 14 TeV Large Hadron Collider (HL-LHC), a high energy 27 TeV LHC
(HE-LHC), as well as a potential 100 TeV future circular collider (FCC). The
HL-LHC has sensitivity to narrow $Z^\prime$ resonances consistent with the
anomalies. In one of our simplified models the FCC could probe 23 TeV
$Z^\prime$ particles with widths of up to 0.35 of their mass at 95\% confidence
level (CL). In another model, the HL-LHC and HE-LHC cover sizeable portions of
parameter space, but the whole of perturbative parameter space can be covered
by the FCC.
