The chances of having a 1800 metre vis under such a low cloudbase at 200 feet is unlikely in my experience or rather unusual.
I would disagree with that. Only once ever have I seen a vis below say 2000m combined with a cloudbase below say 500ft.
But you are an airline pilot so you probably see a lot more in the way of weather, since almost nothing (short of total fog) stops CAT going to a destination. Whereas I would probably cancel the flight in many such conditions, due to other factors (low cloudbase -> a warm front -> high tops -> icing conditions in the terminal area).