It's not impossible to do, just very difficult...to do. With the lack of traffic, cars or traffic lights, it's possible. Over in the Leon forums with the 1.4 EcoTsi engine, running on 2 cylinders, many have posted 60+ mpg on a run (paper specs is 57-60mpg combined). Me personally I've done some 'lack of traffic' driving on 40-50mph roads, and on several occasions got low 60s mpg over just under 15 miles. Saying that 4.5l/100km is a very good figure, my 1.0 EcoTSI (over 200 miles, Lon to Manchester) I managed 4.9/100km (57mpg). It appears the 1.4/1.5 ACTs on 2 cylinders are very economical.