Kind of messy/sloppy but take the oil filter off and have someone crank the engine over. If oil is coming through the oil filter housing then remove the oil filter housing (held in by (4) M7 bolts - will need 10mm socket) and change the check valve. (oil feed for turbocharger comes from filtered side of oil filter).
If oil does NOT come through then pull the oil pan and see if the oil pump gear on the crankshaft is just spinning. I have yet to see a failed 1.8T oil pump but there is a first time for everything.
Of course check and see if an the oil pump pick up tube is not clogged.
Let us know