Watching vids and looking at forums on this. I broke mine on drivers side rocker cover but I see there looks like another one on passenger side or am I confused I have an open tube on pass side rocker nothing in it Atlantic British vid shows replacing that one but not the other hmm any help please

 

What year is your Disco 2? I believe The '03 & '04 4.6L engines have a different oil separator unit unlike the older Disco 2 4.0L engines.
The passenger side of the 4.0L engine is the only side that has the black oil separator inserted in the breather tube in the rocker cover.