Spectra of the brightest molecular transitions (with the exception of CN) taken at three different positions: the geometric centre (black), the southern edge (blue), and the northern edge of the circumbinary disc (red; see the white crosses in the moment 0 map of CS in Fig. 2). The zero velocity value (dashed grey vertical line) corresponds to a system velocity of 4.2 km s⁻¹. The dashed grey horizontal line shows the value of 3σ (see Table 1). Some of the spectra are multiplied by a factor of three, as indicated in the top right corner.