FL TWO HUNDRED tends to be used in UK airspace and as far as I remember it's in the CAP413.
Saying FL two zero zero is an ICAO thing and most other countries use that system.
There are some fundamental errors performed here since we don't fly on FL until passing the transition altitude on climb out. So if I were in the Crew's shoes, levelling off at altitude 2000, alarm bells will be ringing especially if I were PM. Also, did the Crew actually set 1013 at 2000? Just wondering because if the QNH was low say QNH 1000 then they would have been even lower than they thought.
When I was operating in Europe, saying altitude or FL on your read back was very common but the rest of the world doesn't seem to think along the same lines.