Yes, welcome to the forum & good work in seeing 60mpg on the trip with only 180 miles on the clock. As others have said, the trip is a bit optimistic but register the car on Fuelly & just watch how the figures gradually increase over the first 5000 miles as the car runs in.
Once it's got a few more miles under its belt, you'll be able to get 70+mpg on the trip on a decently long journey if you drive carefully.
Fuelly also gives you an average mpg over your last ten fuel-ups, though for some reason this isn't publicly viewable - my latest running total is posted below. And that figure includes cold starts, some short journeys & a bit of shuffling cars on the driveway.
The 1.2 500 has the potential to be one of the most economical petrol cars you can buy.