So does this mean that the 200m refers to vertical separation not the actual distance between the planes ?
Recorded data from the two aircraft showed that the minimum vertical separation was 650 ft at 1213:37, when the two aircraft were 4.1 NM (7.6 km) apart laterally. The minimum lateral separation was 1.6 NM (3 km) at 1213:51, when the aircraft were 870 ft apart vertically (Figure 4). At that time both the vertical and lateral separation were increasing as the aircraft were tracking to intercept separate one-way routes. The vertical and radar separation standards were re- established a short time later.