I have lost Dimension Style and Text Style from the Default Tray, can’t find them anywhere. . Not available within 'manage tray options. How do I restore them?
Are you referring to SketchUp or LayOut?
Neither of these exist in SketchUp.
Good point, SketchUp
Look in LayOut. I bet you’ll find them there. 
In SketchUp the Text and Dimension settings are in Model Info.