That was 14 years later. The initial privatisation was in 1999 and retail went to AGL and power distribution was sold to Cheung Kong Infrastructure from Hong Kong. They retain majority ownership. State Grid of China is a much more recent investment in transmission and not as controversial as the original privatization of the entire public utility. Australia isn't against foreign investment or Chinese investment in particular. I added China more or less as clickbait but the real problem was the lack of public interest and the impact it has had on livability and the economy. I believe the SA grid operator has the highest profit per customer in the country which probably means they are some of the highest per customer in the world.
The 200 year lease was mentioned as it is unusually long and there was some misrepresentation over the length of the lease to people who voted for it and the public.
The question of sovereign interests is real. The original nationalisation in the 50s or 60s was I think due to issues the state government had with the British owners interests not aligning with the state's ambitions. But at the time of sale tensions with China were not the same and the problem was that it was a terrible deal for the state that led to a subsequent explosion in power prices.