Normally the second breather is in the cam cover, but you would rather use the blanking plug under the turbo in the block (good idea).
However, normally this is used for the oil return hose.

So instead use some fittings to plumb the oil return hose into the sump plug hole, as this is the ideal location below oil level, so there is no crank pressure blowing the oil return back up the pipe into the breather tank.

Hope it makes sense.
If not speak to GGR, i got the advice from them.