That's a shame
I'm running a 5 month / 7,900 mile old old model Cooper S and rattles are
very rare events 
It had a nasty squeak in the middle of the dash when it was new, but that went away (and stayed away) after substantial GTT front upper and lower strut braces were fitted
Having said that, I remember test driving a very new
MCS in 2005 and it rattled really badly; it put me off the idea for some time
They seem to be fairly inconsistent
The softer ride of the new car should, theoretically, make it less prone to rattles
Tigger.