  We investigate the effect of including the HERA run I + II combined cross
section data on the MMHT2014 PDFs. We present the fit quality within the
context of the global fit and when only the HERA data are included. We examine
the changes in both the central values and uncertainties in the PDFs. We find
that the prediction for the data is good, and only relatively small
improvements in $\chi^2$ and changes in the PDFs are obtained with a refit at
both NLO and NNLO. PDF uncertainties are slightly reduced. There is a small
dependence of the fit quality on the value of $Q^2_{\min}$. This can be
improved by phenomenologically motived corrections to $F_L(x,Q^2)$ which
parametrically are largely in the form of higher-twist type contributions.
