I flew LHR-EZE via MAD and back in November on IB.
While the service itself wasn't bad there just wasn't very much of it. The flight from MAD-EZE takes about 12hours . About 90 mins after takeoff they served some food and then again about 1 hour before landing a light snack. Apart from that there was nothing else. Drink and very small snacks available from the galley if you required them. What I found very suprising was that there were no trays of water or juice brought around during the flight.
There is no individual IFE in Economy even on the brand new A340-600.