JAR operators are required to have the required RVR by the former OM point, now called the equivalent point, usually around 4d from the threshold.
The controlling factor is the touchdown RVR, which in the case of Cat 2 is a minimum of 300 m.
If the RVR drops inside this point, you are allowed to continue to minima and either land if the correct visual cues are available, or else go-around.
The A320, 21 and 330 are quite capable and certified to autoland Cat 2