Disco 2 td5 rocker cover breather pipe spewing oil out,,, what can be causing this

Td5 disco spewing oil out rocker cover breather,,,my head done rite in with this prob. What are the main causes of this prob.

Glazed bores, worn rings, blocked oil ways(drains) in head, blocked breather filter, is the loom full up to ecu?

Agree with freelance, worn rings bores allow pressure to escape into the crank case and this will blow out of the breather taking some of the oil which is flying around in there.
TD5s are notorious heavy breathers, how much oil are you talking here? What milage do you have on this engine? How much do you have to top it up ?

New injecter harness, injecter seals ecu harness clear, oil spews out breather into turbo and then into piston bores,,, like a garden hose pipe.,, 162 k miles,,,,still.has plenty power and goes well

After checking prob more vigorously seems that the head is cracked, but thanx for the reply