And no you can't really complain at the state owned power company. That's like fighting the wind mills or like that scene from South Park with the cable cancellation.
It's pretty simple here. And yes, you ring the state owned generator, speak to a real person and explain the issue of higher (or in my case, lower) voltage.
I measured and logged over a period of time, on bright sunny days, dull days, heavy load periods, peak periods etc and determined that due to a recent voltage adjustment, our street voltage was outside the tolerances allowed, and too low.
Within a week, they have set up logging equipment and within three weeks they placed two more loggers (one on the street pole and one on my switch panel) as we had discussed possible losses in my house drop and I wanted them to rule that out. About two weeks later, they returned, informed me the street voltage was too low and simply returned the tap on the street transformer (they have plenty of taps for trimming voltage) to where it was prior to the wholesale, area-wide drop of nom 240V to 230V.
Obviously, you need to take into account solar feed in issues in Australia, where the nominal grid voltage can be artificially lifted by the inverters all needing to be higher in voltage to feed in current. But even as I type this, in the evening with no elevated voltages, no solar and around peak dinner cooking time, I am sitting at exactly 240V, which is where I like it. 230V may be the new nominal, but we are on a spur-like feed with perhaps 26 homes and the upper section (about 500M) is run from a single transformer. So I can see some pretty significant swings.