"Let's face facts here. Thatcher was so hell bent on damaging her own Country,..."
First of all, Lady Thatcher's "own" country was the United Kingdom, not England. But, if what you contend is true (which is far from a "fact") why do you think she was so intent on damaging the UK or any part of it? And just out of curiosity, were you around (and more importantly, trying to earn a living) in the 1970s?
But back to more sensible matters, I don't actually get the point of requiring a "super majority" for major constitutional changes. Why should the status quo be afforded such an advantage? Examine it the other way round (using the Scottish Independence issue as an example): "Unless at least 65% of those voting choose to remain in the UK, we'll be leaving". Fair? Certainly not. So why is it fair the other way round. Using 65% as the threshold, almost two out of three people could vote for a change and it would still not be implemented. and that's not very democratic.