Accuracy of the velocity distributions determined through isotropy assumptions (v_iso) for the objects in our simulation using the Gaussian annulus prior (of which the speeds are shown in Fig. 4) that are in the solar neighbourhood at a certain point in time. This accuracy is estimated by dividing these distributions by the actual speeds (v) and evaluating v_iso/v every 50 Myr, for GC isotropy (top row, through Eq. (3)) and LSR isotropy (bottom row, through Eq. (4)), and for Maxwellian kick distributions with different values of σ (columns), shown in normalised 2D histogram with v_iso/v bins of 0.1 and time bins of 50 Myr, in units of (500 Myr)^–1. The black lines show the medians of the distributions.