  We provide an overview of RBC/UKQCD's charm project on 2+1 flavour physical
pion mass ensembles using M\"obius Domain Wall Fermions for the light as well
as for the charm quark. We discuss the analysis strategy in detail and present
results at the different stages of the analysis for $D$ and $D_s$ decay
constants as well as the bag and $\xi$ parameters. We also discuss future
approaches to extend the reach in the heavy quark mass.
