I'd imagine they are thinking of Austal as a builder for the OPV's? No other contender really exist's there currently that could build a ship of that size as no one else has the infrastructure in place.
Would take time to build the facilities and Austal really is the only one there that has such facilities in place, No time for any one to build them considering the tight time frame.
As for the frigates, Even though the BAE made it past thr first round I don't see it being chosen. Time frame just too tight and it needs too much work, Now that we have had our experiance with Navantia and know what to look out for I see that being our best bet assuming they upgrade all of the old crap in them.