Modelling of the lens galaxy light profile. Left: Isophotes from the final light model plotted with data isophotes in the inner region of NGC 6505. The lensed source emission and emission from other compact sources are visible in the data isophotes. Middle: The difference between the data and the model, normalised by the noise in each pixel. Empty pixels are those masked from the fitting procedure. The residuals here show no evidence of a central strongly lensed image. Right: The lens light subtracted data, to be used for strong lens modelling presented in Sect. 3.4. The white circle indicates the compact source of emission included in the lens model.