RV extraction on the ESPRESSO dataset of τ Ceti, after binning observations based on their BERV. Each bin is attributed a unique color. Top: residuals between the RV time series of s-BART and the CCF. To ease visualisation, we plot the residuals as a function of the time difference between the observation and the first observation of the night it was taken in. Bottom: slope of the first degree polynomial that is fitted to the RV residuals, as a function of the median BERV in the corresponding bin. The squares represent the bins that only contain data for one year, whilst the circles have two or more years of observations.