Jaguar XF X350 Engine start-up w/out s/c

My newly acquired X350 makes a rattling sound when being started. My mechanic believes it's from the timing chains, but the opinion in the forums point towards the supercharger. Here the engine is started without the s/c connected. Please note that my microphone has problems, causing the sound to drop randomly. When I played this video on my iPhone it sounded quite awful, but earlier on headphones you can hear pretty well what's going on, which is why I decided to upload anyway. Opinions please :)