Thanks for the quick reply, I tried flashing the stock boot.img from the 4.2.2 OTA I got here in the Firmware.zip - https://drive.google.com/uc?id=0B-kSF8g8H7KuWEt5RVdqajVuaTg&export=download but it made no difference.
My kernel version is -
3.4.10-g23358b6
[email protected] #1
SMP PREEMPT
Is that...