Distribution (left) and average vertical velocity (right) of our sample over the Galactic plane. This is binned, with each bin covering 0.5 kpc in R and 10° in ϕ, both in galactocentric coordinates, with stars in the disc rotating in the negative ϕ direction. We note that moving radially outwards from the position of the Sun ${\overline{v}}_z$ rises to around 10 km s⁻¹ before falling to below zero, but that this behaviour disappears for ϕ ≳ 220°.