Model 2 for MG J0751+2716. The model consists of an ellipsoid power-law mass distribution for the main lensing galaxy G3 (blue cross) and five SIEs for the group galaxies, with an external shear. The observed positions are the open circles and the predicted positions are represented by the crosses, with all positions given relative to component A1. Each colour corresponds to a different background source component (filled circles). The lens critical curve is shown by the thick line; the dashed line shows the source plane caustics. The grey lines are the 3σ contours of the extended emission detected from our global VLBI imaging, for reference. The mass model parameters and their uncertainties are given in Table 2.