I'm not sure about the bailey oil breathers but the spec r one I have on my cossie is plumbed in as follows

The lower port on the circular tank has a pipe which runs to an adapter screwed into the engine block on the drivers side. From the factory this hole is bunged with a threaded metal boss which you remove and screw an adaptor into. The bung is located just above the knock sensor above the front diff, the bung normally has the knock sensor wiring attached to it which you need to remove before taking the bung out. Thread size in the block is 3/8BSP so you will need a suitable adapter to fit this size of thread and a suitable length of hose.

The first top port on my breather system is plumbed into the existing kidney box which is located just under the inlet manifold (black box which looks like a kidney). Looking at your engine bay picture this pipe is already plumbed in, some people remove the kidney box and plumb the breather hose straight into the engine block.

The second top port on my system is plumbed into the rocker cover, again this needs an adaptor fitting so you can plumb the pipe work in. Some people don't use this port at all which is why yours maybe blanked off.

The third top port on my system is plumbed into a breather tank which is located over by the drivers side turret in the engine bay. This allows the gases going through the breather system to escape to atmosphere. You don't need a dedicated breather tank some people just let the hose breath to atmosphere with a small crankcase breather filter on the end of the pipe.

I hope this helps, I'm not an expert on breather systems but the above is how my system is plumbed in and it seems to work fine.