That legislation already exists. The police can do a proper data freeze raid already. What is needed is a search warrant.
The issue here is different. The powers that be deliberately turned a blind eye on the activities of a company because it has been repeatedly useful to "us" in influencing public opinion in various places where we would like to interfere in the democratic process. They conveniently forgot that CA are a private company and will tout for and get business in addition to the government approved election interference contracts.
While the US and UK governments were turning a blind eye (they could have found a reason for a search warrant ten times by now), the journalists did their job. They actually did some proper investigative journalism of value to the society as a whole. Hallelujah, the profession and the idea of free press are not fully dead yet. There is some twitching observed in the rotting corpse and let's hope it is not the putrification gas escaping from it.
As a result the CPS, the Data Protection commissioner and everyone else got caught bang in the middle of turning a blind eye on CA activities. This is the reason for all the panicky motions by each and every one of them. They are pretending to do something while ensuring that CA has enough time to get rid of any incriminating evidence.
There is a lesson in this - there is sh*t which you do not outsource. Ever. If you do it is guaranteed to hit the fan later on. Similarly, an information "soldier of fortune" is a soldier of fortune none the less. We have been through this during the "private run" wars in Africa and Latin America in the 70-es and 80-es. We should have learned the lesson (and applied it).