"as it then was and as the electorate were fooled into believing"
I recognise the rest of your points about the EC changing into something quite different (or rather to be more accurate having something quite different grow out of it as the EC aspect/functions are all still there so far as I can tell), but this comment seems to imply that the EC was not what it said it was at the time of the referendum. Forgive me if I'm reading into your post too much, NJ, but this implication smacks of something distastefully like conspiracy theory - and to be quite frank with you I think you're smarter than that.
I also find the idea of an electorate being 'fooled into' something a bit fishy, if I'm honest. Not that it's impossible, exactly, I just think it's so unlikely that citing it can be a little bit intellectually lazy. I don't view the 1975 results as foolish, personally, but theoretically if the electorate makes foolish decisions, then I don't believe it's because they're 'fooled' into making them - I think the reason is that the electorate are or can be foolish.