text: Thanks for investigating it.
  To answer some of the questions - you can add these "notes" at the osm.org website by clicking the "note" icon (second from the bottom at the right-hand side) and moving it to where you want to create it.
  I think that lots of details in note comments and resolutions is good :)
  Yes, please do make a map edit to fix the problem if you resolve a note (you've been there, so you're best placed to edit it).
  Personally I use both notes and fixme tags - notes are a bit more "in your face" if you have the osm.org notes layer turned on so for things like "I must check the name of that shop" I'd use a fixme rather than a note, but for comments that I'd like everyone to potentially see I'd use a note.
  Best Regards,
  Andy
  