Not to be pedantic but NPD was not introduced by the SNP. NPD was in use by at least two local authorities in 2006, before the SNP came to power.. And it is most definitely a PFI/PPP, with only slight improvements relating to the disposal of any residual assets.
See this 2009 rport from Mark Hallowell and Alyson Pollock. http://www.sps.ed.ac.uk/__data/assets/pdf_file/0003/64353/NPDOs.pdf
The introductory paragraph (remember this is 2009) says : "the decision to continue with private finance carries a high economic cost".
So, while continually attacking "Labour" PFI, the SG has been on an orgy of PFI of its own, hidden behind the fiction that NPD is different and the debt will somehow be less if the SFT goes along with the pretence.