Hi Anto78,
Plenty of info on here about the 1.3 diesel 75HP with the 6 speed Duralogic Gearbox. As a general rule folks like them, I love mine. MPG wise, always difficult to answer, depends on how different people drive, car set up, type of driving e.t.c, but mine never drops below 50, and is even better on a run.
Gearboxes are good with no serious recurring faults, though the odd fault can happen. Same as in a manual box, which is what it is anyway, all that makes it auto is the computer operates the clutch, yes it has a normal clutch.
Hope that helps. Cheers Qube O.