Hello gusfagan, welcome to LQ,
If you have a directory /etc/X11/xorg.conf.d check if there is a file "??-keyboard-layout.conf" where ?? is any number. If the file isn't there but you have this directory, you may copy (as root or with sudo) the file from the /usr/share/X11/xorg.conf.d directory to the /etc/X11/xorg.conf.d/ directory. If you have the file there change the line
Option "XkbLayout" "de"
here it is "de" for germany, default is "us", put your countrycode, probably "uk" there.
If you don't have this directory, you may find a similar file in the /etc/hal/policy/fdi directory and can change the file, don't forget to restart the hald-daemon.
Another possibility is to change the .xinitrd in your home-directory with the line
or whatever code UK has.