I think there is a case for saying that referendums to authorise major changes should require more than just a simple majority.
For example, it seems unreasonable, in respect of the Scottish Independence referendum, that the UK could have been broken up on the strength of a 50.1% to 49.9% majority. Such major changes should perhaps require a 60–40 majority. Or they should require two votes, held some years apart, to see if the result is the ‘settled will of the people.’
However, those rules ought to be in place before the referendum takes place. It’s not right to promise the result will be implemented on the basis of a simple majority — and then try to change the rules after the competition has taken place.