Observations, models and residuals of intensity, velocity and velocity dispersion from the [OIII] 5008 Å line. Models are shown both for each disc (column 2 and 3) and for the two superposed discs (column 4). Residuals are the observations (column 1) minus the two superposed discs (column 4). On the velocity maps of individual discs, iso-line-of-sight velocity curves are represented in black dashed (resp. solid) lines for values below (resp. above) the systemic velocity of the disc.