From one of the FAQ's or the wiki somewhere I found that You need to set up a file called config.txt.
With parameters to set up the screen size. Mine is as below, but remove most of the commented lines and comments following /.
# Set stdv mode to PAL (as used in Europe)
# Force the monitor to HDMI mode so that sound will be sent over HDMI cable
# hdmi_drive=2 /not needed
# Set monitor mode to DMT
# hdmi_group=2 / not needed
# Set monitor resolution to 1024x768 XGA 60Hz (HDMI_DMT_XGA_60)
# hdmi_mode=16 /not needed
# Make display smaller to stop text spilling off the screen
overscan_left=25 / increased from 20 to get left edge showing.
I increased overscan_left from the suggested 20 to 25 to get a couple of mm of space at the left of the screen.
This is on both debian and fedora. I am still struggling to get the login working on the fedora system