Simon Parkes:
I know (or think) it's something to do with the file /etc/sysconfig/i18n but I can't figure out how to setup the rest, are there defaults that these variables should be set to?
The perllocale man page has a section on LOCALE PROBLEMS which may help. I believe this is controlled by the /etc/locale.conf file on Debian, so presumably the i18n file is similar?
The Locale documentation says this about configuring new ones:
To compile the locale data files you simply have to decide which locale (based on the location and the language) and which character set you use. E.g., French speaking Canadians would use the locale fr_CA' and the character set ISO_8859-1,1987'. Calling localedef' to get the desired data should happen like this:
localedef -i fr_CA -f ISO-8859-1 fr_CA
We use the same character set, so presumably replacing fr_CA with en_GB would fix it. You're better off finding out the correct way for your distribution, though.