"If you think polling 16 million people in a rich country is more complex than polling 815 million people in a poor one, please sit down and have a rethink. It is very very hard to fathom that difference in scale."

I think you have misunderstood my argument. I totally agree that the Indian election is more complex. But I argue that complexity comes from places other than the counting itself, and returning to the subject at hand that means India's size and complexity in no way leads to the conclusion that its elections or anyone else's elections "pretty much require electronic voting". So in what follows I will examine the "ideal" case and then the rest of the issues.

In the ideal case, if we imagine a theoretical Westminster system with first past the post voting, we can pay 10 people to organise 250 volunteers per electorate of a theoretical 200,000 voters. They all start counting at the same time when polls close. In this system there are always 800 votes per volunteer to count. It doesn't matter how big the population gets there are always 800 votes to count for each volunteer. Population of 1 million? 800 votes per volunteer. Population of 8 billion? There is still only 800 votes per volunteer. So the system is scaling with the population. Thus India having 51 times (using your figures) as many voters as Australia does not mean it's 51 times more complex to count up the votes. Similarly, nobody would claim that the counting the votes in the UK election is somehow magically 3 times as complex as the Australian one or that elections in Australia now are many times more complex that elections in Australia 100 years ago.

Of course, leaving the ideal case somewhat, due to natural human variability a larger system will have more electorates that return their results slightly later. Indeed in an infinitely large imaginary system there might be an electorate where all 10 officials in one electorate die of a heart attack and it takes two days to get officials from other electorates to show up and do the count. In the real world with real humans, but still presuming they were operating on the exact same rules, the larger system (say the UK or the USA versus Australia) would likely have later returning results, but not by much. It's also worth remembering at this point that in many elections the last electorate to return a result is often irrelevant to "the ultimate result" as someone already will have a majority much earlier, many elections are conceeded by the loser well before the final tally comes in.

That there, in the ideal case or the "same system" with real people, is the basis of my objection to your comment that "for a place like India, the problems pretty much require electronic voting. I am old enough to still remember paper ballots in India. Imagine having to count of the order of 600 million(!) votes". I am not saying there aren't other sources of complexity: many languages, poverty, illiteracy of some voters, poor transport and corruption will all take their toll. But those problems are not solved by voting machines either. I continue to maintain that 600 million votes does not in any way shape or form "pretty much require electronic voting".