Hi Ashley,
As Chris mentions, I'd check each of the cam oil feed filters (one per bank) which shouldn't take too long.
I did find getting the NS one out what quite tricky as there isn't much clearance. So maybe start on the OS and see what condition that one is in before deciding if it's worth checking the other. Mine were both spotless at 130k.
Good luck and keep us posted.
Cheers, Lee