Hmmmmmmmmm, embarrassingly it just installed. However, I am still in American. Here's what I did...
cd /home/software
wget http://sarkpbx.com/sail/languagepack/Asterisk-1.4.28+/sme-ast-en-uk-gpl-sounds-1.2.0-4.noarch.rpm
yum -y install sme-ast-en-uk-gpl-sounds-1.2.0-4.noarch.rpm
However, I now can't find where to put
language=en-gb
Also, I was expecting to see a en-gb folder somewhere (old or new Asterisk locations) but I cannot find that either. What am I missing or what have I messed up?