I'm not sure if it was Wimbledon or the Doctor Who announcement that distracted me, but I completely forgot to check on Saturday night whether there were any new opinion polls. As it turns out there were two Britain-wide polls - one from Opinium and one from Survation. Both had the SNP slightly ahead on the Scottish subsample...
Survation: SNP 33%, Labour 25%, Conservatives 24%, Liberal Democrats 14%, UKIP 4%
Opinium: SNP 35%, Conservatives 31%, Labour 29%, UKIP 1%, Liberal Democrats 1%
Survation's subsamples are always particularly small and not correctly weighted, but as it happens the recalled vote of the sample on this occasion is reasonably close to the actual result in June, so there's one less reason to be sceptical than usual.
In conjunction with the SNP's creditable near miss in the Elgin by-election, where the swing against them since May was negligible, I'd say these new figures move the balance of probability back towards the SNP having some sort of continuing lead in Westminster voting intentions. There have now been nine Scottish subsamples from various firms since the general election, with five putting the SNP ahead, three putting Labour ahead, and one putting the Tories in front. The SNP have never been lower than second place, whereas both Labour and the Tories have been third some of the time.
My best guess is that if a full-scale Scottish poll of Westminster voting intentions was conducted now, it would probably show the SNP with a narrow lead over Labour, with the Tories in third place. I certainly wouldn't exclude the possibility that Labour have a small lead, but I don't think there's any real danger that the Tories are ahead.