In the scope of solar cell characterisation, spatially resolved imaging (SRI) methods (EL, PL and LBIC) have long been a standard procedure for valuable in-depth evaluation and extraction of various spatially resolved material properties, especially those related to the electrical behaviour. While this extraction can be straightforward in the case of laterally homogeneous devices, the situation is vastly different when the structural features are laterally varying, such as in the case of interdigitated back contact (IBC) solar cells. We show that in the case of laterally varying devices inherent device optical properties play a far more important role in determining the measured profile in this case and may indeed overshadow any underlying electrical effects. We therefore propose and validate a methodology that couples SRI characterisation with advanced bottom-up simulation of IBC solar cells. The method fully accounts for lateral device variability and allows for accurate extraction of the underlying electrical phenomena. We demonstrate the applicability of the method on state-of-the-art high-efficiency IBC solar cells, and explain the key factors, which could lead to misinterpretation of the results obtained solely by SRI measurements. •Interpretation of measured IBC electroluminescence profiles through opto-electrical simulation.•Decoupling of underlying optical and electrical phenomena.•Device optics overshadows recombination driven fluctuations of luminescence profiles.•Rear interface strongly influences the shape of the extracted luminescence profile.•Shape of the luminescence profile is highly dependent on imaging system’s aperture.