My phev gets 45mpg from the petrol engine so 49 mpg sounds about right for the diesel. Yes it is good for a fairly large SUV, my evoque got the same mpg (45) and it was smaller than the kuga and a diesel.
I also think the mk3s do much better on fuel than their predecessor. There's lots of threads from people with mk2/mk2.5 complaining about fuel economy.
Since mines a Phev, The only complaint I have is the economy on EV only in colder weather. It's lost about 15 miles of range.