Trying to update a HUD

I created an object within Game.cs, named _playGui, inheriting from the class GuiPlay : GUISceneview, IGUIScreen like this:

GuiPlay _playGui = new GuiPlay();
GUICanvas.Instance.SetContentControl(_playGui);

Now, what I want to do is to create a use this as an instance I can use through the code so I can update the HUD with scores and such.

So I have added:

public GuiPlay Instance
        {
            get { return _instance;}
        }

and:

#region Private, protected, internal fields
        private static GuiPlay _instance;

But when I compile, I am getting the error:

Inconsistent accessibility: property type 'StarterGame2D.GuiPlay' is less accessible than property 'StarterGame2D.Game.Instance'

Is there a way to fix this, or do you guys thing I'm going at it the wrong way (my intent being having HID scene objects associated with individual GUI components that then can be easily moved around in the editor).

Thanks!