My problem wasn't Entitlement Check
I was using the stock mobile hotspot and although I could connect to the hotspot from other devices and my XT925 could itself access the Internet, connected devices couldn't access the Internet.
After installing the SQLite app I found that the Entitlement Check was already set to '0'. After some research, I found that I had to add 'dun' to my APN type in my APN settings. It's odd as my APN settings were exactly the same as I was using on my LG Nitro HD with the same provider.