for some reason my screen has gone and shrunk and when I go to display and click on mirror screen it doesn't seem to do anything.
Not quite sure what you are asking/saying. Are you talking about your whole GNOME or KDE display?
You can reconfigure X in ubuntu by running:
sudo dpkg-reconfigure xserver-xorg
It will bring up an automated "wizard". You can answer the questions and it will reset X to the newly desired display settings.
I changed the resolution to the highest one available and it worked
thank you so much for taking the time to answer my simple question.
I noticed that the simpler questions get brushed aside in these forums, and it makes learning a much slower progress especially when you can't find answers though google.
The one thing left now is a small box in the top left hand corner which has ‚ÄúLaptop 16'‚Äù written in it. So just wondering how to get rid of it. As I don't think I want to be boasting about my 16 incher.