I've got some oil come through the air intake which has collected on the bottom right side of the air filter. Does anyone have any advice on changing the PCV valve? Where is it located and is it a simple replacement job?

I'm hoping it is the PCV valve but am also getting a P300/P306 code, although the engine does not appear to be misfiring, so if anybody has had similar and has any advice please let me know.

Cheers