Hello and Welcome! I'm Billy and i will assist you with your inquiry. Feel free to ask if any further info is needed.
does the knock come from the front or rear area?
by full lock, do you mean differential lock, or steering to the max?
front end, while turning steering it doesnt just happen on full, i also hear it while taking the lock as well
is it a crackling cyclic noise (clac, clac, clac)?
If the noise is cyclic as described, then the most likely fault would be the drive shaft joint(s), to be checked for clearance and replaced accordingly.
If not, then the most likely reason would be a suspension item (ball joints, bushes, etc...)
The most common cause on your model being Worn ball joints on anti-roll bar link rods.
So you need to double check these while checking the suspension.
Get back to me with your findings or if further info is needed.