There is no water in petrol, carb-icing is due to atmospheric moisture condensing and freezing. Quite why your bike doesn't suffer icing when using a different fuel I can't explain, but it isn't due to water in the fuel.

As for V-Power or other super unleaded fuels, I've never bothered with them personally, even for the track bike, but I'd be interested to read anyone's objective appraisal of a true comparison to see whether the additional cost is worth it.