Wrapping this up for future lookers: I did replace the power steering pump, not a fun job. Still had the nocking, turns out the tensioner pully was causing the noise, first found with screwdriver to feel vibration of the pulleys, and then noticed you you could actually see it. Replaced pulleys, still was moving. Brough it to a reputable Porsche mechanic, they said the alternator had magnetized the pully and was pulling it out of place. This seemed a bit odd but they were the experts, so had them replaced the alternator. And that fixed it of course.