Found the answer, Nuget packages are installed to a location that was not reflected in my Nuget Package manager correctly.
The location on my computer for Xamarin was "C:\Users\[YOUR WINDOWS PROFILE NAME]\AppData\Local\Syncfusion\EssentialStudio\15.3.0.26\Xamarin\nuget".
Go up to 15.3.0.26 folder and choose your poison for other technologies.
XamDev Dave