The first comment on that article (clearly posted by a pro-Indy person) if correct might explain your numbers:
"Lies, damn lies and statistics as someone said. This poll actually reported that, excluding don't knows, 49% of respondents chose one or other of the pro-independence options and 51% chose the sole anti referendum option. In other words the exact same result as other recent polls"
No idea how true that it as I can never figure these things out but your initial delight at the headline might not be so clear.