Unfortunately for the Indy wing, the issue that has caused Irish reunification to become more likely (the EU confirming that border controls would be necessary between the UK and the EU) could potentially cripple the swing vote. After all, last time the SNP could make an argument that border controls would at worst be a temporary annotation, this time round the explicit aim for the SNP is to rejoin the EU, which means border control in the long term.
This is a great point. I never underestimate the British establishment's ability to things up in general, but I also think the legacy of british history makes hard borders something no one would want.
Also is there actually going to be a referendum on reunification, or is that just a rumor?