Re: blah, blah, blah
Well, 67% voted to join in 1975. Now that’s what I call a mandate. It covered both the Common Market (the trading bloc that you refer to) and also the EC, the predecessor of the EU.
With regard to further integration, that was covered in the manifestos of the political parties involved - and we all had the choice to elect them (or not). In fact, this provides the only real legitimacy of the Leave vote - in that the Tory party got elected again.