On initial start up mine revs to almost 2000 then dies down. Normal idle, when up to temp is about 1100, dealer said use the manual idle adjuster (well spotted Mr Kean) to set my own speed! Seems to be a personal preference.
A neighbour has just bought a new Jaguar sporty thing and that does the same and apparently is the new normal, to fire up on a high rpm for a couple of minutes then down to a normal rpm. Hers sounds great at 6am every morning

all probably due to emission levels and controlled by the ecu.