Guys is there any patches/solutions for this - this is a pretty big issue that I'm surprised to see doesn't seem to have been addressed much.
I flashed CM 11 - Snapshot-M5-i9300 and Gapps, but the mobile/network data still doesn't work. Is there any Radio files or anything I would need to flash?
I've fixed it! For some bizarre reason it seems when flashing any custom rom, you would need to manually set up the roaming/data settings that your mobile network can provide you. I simply fixed this by going into Mobile Networs > Access Point Names, selecting my mobile network (02) and amending the settings, rebooted my phone and voila 3G full works!!