Immigrants in public office

I recently pointed to Ed Miliband's unsuitability for public office on the grounds that he is insufficiently British. His parents were immigrants to the UK and by my reckoning there needs to be a least two generations of family to qualify. (see   here).
There is another who would fall foul of this rule as I pointed out over two years ago here.
The Baroness who sits in the House of Lords has been attracting attention for allegedly favouring friends when public contracts have been awarded. see here.
I'm sure its all in order but my argument still holds. Two generations MINIMUM before a family member can hold public office.