We have done much the same on our 2008 D365, swopping the original Raymarine chartplotter mounted under the sprayhood for an Axiom 12 Pro on the binnacle, but keeping all the other original Raymarine bits. It is a huge improvement having the chartplotter (along with depth, SOG, COG ETC) at the helm. I also have the Navionics app on my ipad, as backup and as a second chartplotter. I agree it is annoying having to take out two subscriptions.
The membership association for owners of Dufour Yachts