This has been seen on TFSi cars.
Headgaskets have been known to go but the two most likely causes are
1) HPFP issues
2) Piston seal issues
Note that all these engines have oil that stinks of petrol - be sure you are not being paranoid by sending an oil sample to an independent company that samples oil. For twenty quid or so they will supply you with a test kit which is easy to use an you send the sample away to be analysed and a few days after you send it back, you get a detailed report with all the findings you oils you could want.
It is a lot easier and potentially cheaper than having a mechanic check it at 40+ notes per hour.
I sent a sample off from my 2010 Cupra when I also thought my oil stank of petrol but te test resut was perfect - the type of oil in the engine may smell a bit of petrol once in the engine or a small while.
For what it's worth in my opinion, the oil should be changed at 5k intervals or even more often on tuned cars.