Its quite simple actually – but I had to google for ages trying to find the answer.
wget -q -O - http://www.atomicorp.com/installers/atomic.sh | sh yum upgrade php* mysql*
Bear in mind this will do a server upgrade – but seeing as this is a webserver, its probably best to have the latest versions for everything in terms of less security vulnerabilities.
EDIT> More things I needed to document. Incresing the amount of IMAP connections allowed as Thunderbird was erroring out.