Question [Q] Flashing back to 4.2.2

Hey guys, Hopefully somebody can help me here.

Basically i flashed & rooted my D802 to 4.4.2 using this method > http://forum.xda-developers.com/show....php?t=2680789

All was running fine however somewhere along the line something has messed up! I tried to boot into recovery and now im hit with "Secure Booting Error! Cause : boot certification verify" instead of TWRP!

Ive tried to use this method > http://forum.xda-developers.com/show....php?t=2625044 to flash back to stock and unroot BUT when i get to step 5. of method 1. instead of asking to to Select Country & Language it starts the LGMobile Support Tool and the tool tells me i have the latest available software for my device.

The phone is running fine and i can get into download mode.

Thanks in advance for any help.
Device:- LG G2 16GB (D802)
Rom:- CloudyG3 v1.2
Kernel:- Dorimanx v5.8
Recovery:- TWRP v2.7.1.0
Carrier:- Three (UK)