So after a little testing my Dell T110 looks to be having some hardware issues. Full ESXI 5.5 re-install on a new usb drive. Server 2012 and plexmedia server install fresh. Start to stream a film and the VM locks up and so does ESXi.
So looking for either a new ESX based server or qnap/synology solution. Budget wise no more than £300 I have hard drives.