It's somewhat hypocritical to claim that a close vote would be unfinished business but only if your own side lost. Therefore I assumed that Nigel was talking about a close vote whichever way it goes.
I've looked at the link.
These things are not reciprocal because if we had voted to stay the underlining issue for us to leave would still be there and unresolved for those who saw the need to leave. For me, and them, the EU is like a cancer, the issue is only over when it has been removed. What Farage was saying in the piece was that a future referendum would still be on the cards, but unlike some of the whinging Remainers, he didn't mean straight afterwards, as they are now calling for.
Therefore, and as for the close %age margin, which is what I think you are referring to, this changes nothing. If it had been 52/48 to stay then we would have stayed with the option of a future referendum, years hence. As it is, it was 52/48 to leave and so we have to leave with the option of a referendum in the future to re-join, years hence. The only difference is that re-joining does not get us back to square one in this regard as we would have to start from scratch and lose all our opt outs, and special conditions. We would also have to join the Euro, which you have agreed is a total failure and an abomination to mankind. This is why I say at the top that these things are reciprocal because in leaving and then joining again doesn't get us back to what was (or what we have at present).
What looks to be happening is that Brussels will be forced to radically change its whole plan of the federal state and if the EU does change to EU-light then re-joining at some future date may be palatable for some, or the majority. What might also happen is that the EU becomes an auxiliary institution to the nationl states and so we will be part of it not because we have moved back towards it but because it has moved to the nation states.