Thanks for the direction Nicolas.
The error is:
esotechie.me.uk [Fri Jan 17 10:26:06 2014] [error] [client 86.21.50.55:33697] AH01215: PHP Fatal
error: Allowed memory size of 25165824 bytes exhausted (tried to allocate 107 bytes) in
/home/sites/esotechie.me.uk/public_html/libraries/joomla/language/language.php on line 813
The memory limit is now set to the maximum of 512M but we still get the error which does not make sense to me.
I have also tried deleting the whole site and re-installing everything from scratch and have the same issue.