Hi Oliver
Thanks for taking the time to reply, I will try the revised library and see what happens.
At the moment to get over the problem I have to remove the 5volt supply to the GLCD whilst my program is running, wait a second and then restore the 5volt supply , once the display is showing the correct information it will function Ok, it just appears to be a problem on first power up.
One question, could this probelm be caused by the fact I am not using the display reset (not present on the serial socket which is on a PCB on the back of the display)
U8GLIB_ST7920_128X64 u8g(0, 1, 2, U8G_PIN_NONE);
Many thanks
Jason