Power spectrum residuals for a few additional cases, in the same format as Fig. 7. We note that for the bottom panel, the fiducial model is the best-fit from 30 <ℓ < 800, as opposed to from ℓ < 800, as is the case in Fig. 7 and in the top two panels of this figure. In all cases the black line is the best-fit ΛCDM model in the range indicated by the shaded data boxes. The coloured lines are the linear responses to the shifts in parameters between these two best-fit solutions. Top: same as panel 5a of Fig. 7, but with an additional free parameter, A_L, shown in yellow. This added degree of freedom tracks reasonably well the oscillatory residuals, leaving smaller shifts for the other parameters and a reduced low-ℓ deficit. Middle: same as panel 5a of Fig. 7, but with dashed lines showing the responses with the gravitational potential fixed. Bottom: the way in which the best-fit model from 30 <ℓ < 800 is “thrown off” by inclusion of ℓ < 30 data. We note that although visually the ℓ> 800 data appears to be a better fit with ℓ < 30, the χ² is worse by Δχ² = 3.2.