The problem as I see it with the first EU referendum, was that there wasn't much clearly defined on either side of the argument to tell us what we were actually voting for.

This information vacuum was hastily filled with speculation, rumour and misinformation, and it still isn't clear today what the overall result of either decision would be, so it was a process that was fatally flawed from the start.
As it is it looks like we are going to end up leaving the EU but at a greater cost than previously indicated and potentially without having any effect in immigration, which doesn't seem like it's what anyone voted for.

If a second referendum was held, it would be completely pointless to ask the same question as that would be subject to the same speculations and weaknesses.

If a second referendum was going to be held it would have to be after the option or options for leaving or staying were fleshed out in detail and costed then people coukd have something concrete to vote for, not sone empty rhetoric.