I've owned some noisy bikes but.....

Sounds like someone from the south of England assembled that bike definitely not a Northerner, do not even start that bike again as said get the dealer to come and get it no engine should sound like that.
 
The Rocket Engine is a noisy thing a lot going on in there, but as the others have said that is not normal and I agree take it back without starting it again if possible, sounds like the timing chain tensioner has failed and the chain is just slapping around,
 
I would look at the little book under the seat if they still have them which also has the log for the dealer to sign when he does the checks. As for the tensioner if it released I would be surprised it has not bent and or broken a valve or two.
Good luck
 
BACK to the dealer with that noisy mess
 
The Rockets are not that noisy