Nige, only makes sense if we could trust our lords and masters with an incremental capability declaration programme to match an incremental procurement of essential equipment. Not commenting over whether that is likely or not, but not seen any evidence of it so far! Makes sense to me that it should come as standard, cheaper to put in during build, but also logic in keeping an open mind for over the horizon capability, as suggested by LO.
Let us just hope they get it right....