[Treeve]

Why not just fix the Applicable ADR's in the NCOP (i.e. prevent them from 'updating' the applicable ADR without updating the NCOP document) and say "righto, this is what you have to build to until the next version of the NCOP is sorted", and go from there, and then get a build number and VIN number assigned to a particular version of the NCOP (i.e. NCOP version 2, NCOP version 2.1). Same idea as yours, but gives a greater than 4 year window.

I like the idea of getting the ADR versions that are applicable set in stone at the start of the build though.