Left panel: figure of merit as a function of lens number density in a simulated 1 deg² field. The orange line shows the case where we consider all the galaxies in the field, and thus gives us an estimate of improvement in precision when using a two-dimensional method. The improvement levels off at a value of around 5, which indicates that in dense galaxy fields, the loss of signal-to-noise ratio due to the limited number of sources cannot be overcome. The blue line shows the case where we apply a typical KiDS survey mask to our mock catalogues. Right panel: relative shift of the halo mass M_h (top) and halo concentration c (bottom) derived from the constraints on the f and g parameters from the fiducial model as a function of completeness. Shown are the shift of the recovered parameters for the one-dimensional method (solid lines) and the shift of the recovered parameters for the two-dimensional method (dashed lines). Also shown is a typical completeness due to a mask in a KiDS like survey (vertical grey line).