Took it apart and back together and it is now working, it probably didn't need cleaning but I did anyway, I think when I was putting it back together initially I must have forgotten the one clip behind the LCD, so I think that wasn't fully clipped so it didn't have a good connection so the upper characters did not display but the top ones still did.
Thank goodness, I thought I might have zeroed the odometer!
Thank you for your help!
Well I'm glad you got it sorted in the end