I have accidentally hidden the side bar on the right hand side of the screen and cant fathom out how to bring it back into view
Sidebar. Also you could just press F11 to bring Styles & Formatting in the sidebar.
Check the menu
"View : Sidebar"
( the menuitem “Sidebar” is located about 8 items from the bottom of the menu ).
If you referred how anchor the SIDEBAR to the page’s right hand side, (it’s just happened to me):
After you open it doing ‘Ctrl+F5’ or from the drop-down menu View>Sidebar, you have an independent window.
Left hold click on the sidebar’s frame dragging it’s corner in the corner of the page. Hold on a bit, when the border changes to dashed release the left mouse.