The NAO is a slightly...strange organization, as its brief is, well, auditing, on the presumption that people will spend too much public money if left unattended. The problem with this is that it encounters something like this, where the fundamental problem is that the government needs to crack on and buy important parts of the capability, and it doesn't really have either a remit or a language to say so. The further problem is that if it did, it would be a sort of National Is The Government Doing Stuff Office, and that's really what parliament is meant to do.