I don't believe that it is only the Yes voters who will be voting SNP. Many people are completely disillusioned with the attitudes of the main parties, in particular of the tories.
David Cameron and his chums made such a huge hoo-ha about wanting Scotland to stay in the UK then, when that happened, there has been non-stop condemnation of everything Scottish especially Scotland's legitimate desire to be properly represented in Westminster parliament.
A quick look at the constituency information, linked to by durhamjen on the first page of this thread, shows that most constituencies have around 60,000 to 70,000 voters so the larger population of England will have a larger number of MPs to represent them. There will be no unreasonably large number of SNP, or any other party, coming from Scotland.