There's many a reason why a referendum is not workable without a GE first. There's no majority in parliament for a referendum act. Because it's not just about the concept of the referendum only, but the question in it.
Lib Dems and SNP would support a referendum of May's Deal vs Remain. Corbyn might, but he wants his own deal so unsure. Hard Brexiteers would call that a betrayal because
a) it could reverse previous result before it's taken place and
b) they see it as Remain vs BINO (Brexit in name only) removing the option of "clean break"
The Tories could perhaps coalesce around a referendum of May's Deal vs No-Deal. But there's no way LibLabSNP would lend support for that. There would be no compromise between these sides.
Even if LibLabSNP + Indies succeed in passing an act for Remain vs May's Deal referendum, the Tories and Farage would simply ask brexiteers to abstain to undermine its legitimacy. Then promise to ignore the result if they get reelected since it's only an advisory referendum, against their agreement, that has been undermined as well. Parliament can't bind it's successor anyways.
So really we need a GE and a parliamentary majority first, in order to return to some semblance of normality.
