Doh!

Left the door a jar on the car when I went away on holiday. And a flat battery resulted. I would assume the back up power source would have drained and so the ECU would have to re-learn settings. As the tank has been filled as previously with Super un-leaded should I be confident of this being a reset ECU now?

Any comment if this practice of restting ECU`s is worthwhile?

Yes your ECU will be reset.