Defence spending was lead item on the BBC news last night - can't remember the last time that happened. That does suggest that the subject is elbowing its way in as an issue, and the media has scented that the govt has a big presentational issue on its hands, which is all helpful grist to the mill.
The motion / debate scheduled for Thursday will hopefully help to keep the pressure up, and as has been noted the issue has a good measure of cross party support.