'2-plus-1' roads & Dual Carriageways

What does a 2-plus-1 road have?

Two non-motorway lanes in one direction and one non-motorway lane in the opposite direction

Where may a driver overtake on a 2-plus-1 road

Wait until you reach the 2 lane section (one lane with traffic going in one direction, other with traffic going in opposite direction)

When driving along a dual carriageway in normal driving conditions, which lane should a driver be in?

Left unless they're overtaking or turning right

How often does a two lane stretch occur?

Approximately every 2 km