Weird noise

Evening all , hope everyone is well , I have a 68 plate Skoda Octavia MK3 VRS245 DSG 65k miles 

When I start the car it has a Second rattle assuming that is the oil pressure building up so not bothered about that , once I have left the loonngggg cold start to finish if I gently tap the throttle I get a weird buzzing / rattle when I come.off the rev , doesn't do it when it's fully warm and no noise whilst driving drives like a dream , I have attached video was recorded on phone so engine sounds really loud so just turn volume down a tad lol can assure you engine isn't this loud but listen out for the buzzing after please 

This is the link to Facebook video as won't let me insert here as too large 

https://www.facebook.com/share/v/7Y3osQ6XPs56FMS5/

Noise seems to be coming from behind engine below turbo 

All help appreciated