Grexit, yes, still on the list. (And were I a Greek minister, I suspect I would prefer capital controls followed by Grexit to sucking an additional 1.5% of GDP out of my economy this year and 3.0% the next.) But Brexit? Nope.
First, the polls do not favor it now. Second, I suspect that David Cameron will campaign against it, just as he did against electoral reform. With the election behind him, he would be insane not to do so.