I had thought of that Meikleour but Vilas's reference negates the need to. I remember being told by an Airbus factory pilot that you could fly the A332 with one wing empty and the other full but I have never looked for any similar information for the 320 family until this came up recently.
With the new fuel system a flow of fuel is forced through the jet nozzle creating a suction effect forcing centre tank fuel into the wingtank. If you lose the initial flow there will be no transfer on the affected side.