I accept your point, Davidhs and I admit I don't know the answer. I do think a GE would be a really bad idea for the reasons stated above.
Nevertheless, I can see that a new referendum wouldn't be entirely satisfactory. Perhaps it should be made perfectly clear that it would be advisory and, as I suggested above, in two (or more) stages. Maybe people should be asked if they still wanted to leave/remain. If the result is "leave" they should be asked whether they would be prepared to leave with no deal. They should then be asked what their priorities for a deal would be.
I know that sounds tedious, but if people really are serious about the future of their country, I think they should at least be prepared to spend some time making their views detailed and explicit.