GB - the factory very wisely doesn't quote fuel consumption figures!
I would expect about 45mpg, if the motor is as soft as the 9.5 which runs well (on the one ride I had on it) at reasonable speeds. The latest Corsaro has an improved map which also improves consumption (looks like the Factory has a complex about this).
My exhausts ran sooty just before the 5,000 km service, cured by resetting the mixture at the dealers; it hasn't gone out of adjustment since and I have now had the 10,000 km (6,250 miles) service.
I am on my second rear tyre; the original lasted just on 6,000 miles, so I am probably a gentle rider...
Of course, the Gran Passo will be a totally different beast, and there is also the new "Scrambler" to consider, although that is probably just a fashion statement (but then, aren't they all?)
CC