So I'm fitting a oil catch tank to my sei ( to make under the bonnet look pretty lol) and I'm not sure of what size pipe the breather is could any one tell me its a 03 plate
Buggered if I can remember. Hell, just measure it.
Remember, you still need a take off to the inlet manifold: any oil breather venting to atmosphere (even through a catch tank and a filter) should be an automatic MOT fail.