Foreign anti-interference laws address your first point. If they arent effective, thats easily resolved in parliment.
Don’t conflate foreign interest with genuine opposition, I would be very surprised if there wasnt any. This is the Democratic system working. The hubris of the left is suicidal.
Ruling out foreign interference like astroturfing, genuine Opposition doesn’t come from no where, it comes from suffering in most cases. Failure of elected governments to reflect on their own failure breeds it.
Keep in mind the agency is run by the Government for the Government of the day with people appointed by the Government.They are far from free of their own political agenda.
When you start eluding towards banning democratic parties, you lose all credibility