Who begins or let alone completes an ILS with the RVR reported at 550 feet (or are you talking meters)? Don't most countries have an approach ban for the visibility for Cat I and Cat II ILS approaches?
Yes meters.
Yes the ban is usually 1000ft. if reported rvr is below of what is required ,usually 550 meters(cat1 ils)then a missed approach is to be initiated.
So if vis is 550 meters rvr, then one can continue,however the runway itself will be visible only below 200ft.