Left panel: Stack of 280 WFI exposures of the field of view used for light curve extraction. Stars nominated PSF1 to PSF5 are used to model the PSF of each exposure, and stars designated as N1 to N5 are used to normalise the flux between each exposure. Right panel: HE 1104−1805 imaging in the filter F160W band using HST WFC3. The main lensing galaxy is denoted as G, whereas the main perturbers within 5^″ of the lens are numbered from P1 to P9.