Make sure you put the latest, up-to-date, HornetFCS.dll, that came with the v16.1, into your Panel.Fleet folder. Then, alias the D model's panel= lines in the [flightsim.0] (etc) sections of the D model's aircraft.cfg.
Alternatively, copy the Panel.Fleet folder from the v16.1 over to the D model's folder, and then change the panel= lines to Fleet.
I can't swear to it, but I seem to recall reading someplace the BA cockpit is the only one the D model uses, so the above methods MAY not work. I'll see if I can dig that up, if it exists.
In any event, try copying the HornetFCS.dll file over to the D model's Panel folder. I think that will fix that problem. You DID allow the v16.1 to install the correct NETFramework Release (I think it's called) in while it was installing, yes? It seems to be locked while doing this, but it's not, Go get a cuppa Joe, or a snack, or something, and just let it run. It's NOT locked up. I promise
Hope all this babbling helps a little...
Pat☺