Going back home from Wales

Well yesterday I came back from Wales to Gloucester and done roughly 155 miles in 2hrs and 30m with one stop. I managed to get 51.4mpg out of my car doing 70mph near enough all the way just one odd part with a 50mph limit on motorway and the odd 40mph limit going back home with also the weight of my bike, loads of stuff in a big massive bag, laptop, bodyboard, a bike rack to stick on the back for next time I bought of my cousin, sat nav and of course putting the weight onto the car imo that isn't bad mpg.