One would presume incorrectly - that website is far from definitive - but in this instance their statement is fair enough: Big Ben is solely the bell, but the name is often applied - incorrectly - to the tower (and clock, though I don’t recall that being so common).
No, UK history.
I’m not sure whether to put 
at the end of that. I understand it’s amusing to criticise criticism of pedantry with pedantry, but I really do get annoyed - even slightly offended, TBH - when ‘England’ is conflated with the entire UK. I’m British, from the UK, but that does NOT make me English.
That the English plotters intended to blow up a Scottish monarch is part of the whole point.
