I'm not sure I buy that though Pete. There are typically 30 odd million people voting in each general election. Your odds of making a difference with your vote are worse than of you winning the lottery. As individuals, we have bugger all power in our democracy.
As for the EU, we can vote for MEPs, and we can vote for elected officials to represent us in Europe. So no, we don't have control over government, but then even if we make the naive assumption that a vote gives us some control over parliament here, the majority of voters put their cross in the box of someone other than the elected government, so we have no control here either.
That's politics isn't it?
As for being ignored, yourself and others have been saying repeatedly in the last few months that our crack negotiators are going to sock it to the EU during the Brexit process, so it's a little hard to see if we're so persuasive as we're walking out the door, we'd be utterly unpersuasive when we had a seat at the table. We can't have it both ways, can we?