Aero D
May interpretation of the rules would suggest that you must use VOR or NDB or circling minima if all there is is a Cat 1 ILS.
I think the logic goes that you must consider any single plausible failure at the planning stage, which means that any component of the ILS installation of the ILS (LLZ or GS) could fail. This being the case you alternate weather should be good enough to allow you to successfully complete a non-precision approach.
If alternate only has say a non prec app, then in my company I would need wx of minima + 200ft ceiling and rvr + 1000m. (Ceiling defined as >50% coverage ie BKN or worse).
Does that make sense or not?