A mock up velocity map and zoom in on the surface of the disc wall (10–13 AU) with the slit at PA = 145°/325° and PA = 55°/235° overplotted as solid red lines and the slit at PA = 10°/190° and PA = 100°/280° overplotted as dashed red lines. In the case of 145°/325°, we obtain clear double peaked profiles and at 55°/235° flat topped profiles. The disc inclination is 42° and the PA of the disc on the sky is 145°.