Mortar matching is often seen as difficult to do, but once you understand that historic mortars primarily came from local sources, one need only look to the local geology including at roadside cuts to recognize the aggregates of a sand in their former condition. This is the wonder of the fractal nature of stone reduced to sand. And often the sand you seek is right beneath your feet!
Google Maps for mortar matching?! Go local when seeking to match historic mortars as the sand you seek may well be under your feet. If you need to go off site, look nearby. When the mortar analysis checkbox is clicked by sending away for a report that does not give you an exactly matching source (without relying on tweaks from pigments that may not be stable and will change the lime-sand ratio of a mortar and its working properties), your money is being wasted and your building is not getting the best treatment.