I don't think that bothers them. They now have enough seats in parliament to kick up a fuss. And if the Tories aren't promoting any policies that will benefit the Scottish people, the SNP will just call for another referendum. Something that probably couldn't happen if Labour/SNP were in power.
The UK government has to grant a referendum, the SNP have been elected without a mandate for one. In short - they can't have another one, literally no way they can without being elected, including it in their manifesto and shouting about it during an election campaign.
They'd also loose if they had another one, probably worse than they did last year.
The English seem fixated on giving Scotland another one, the SNP are in Westminster to represent us, not break up the UK.