Estimates of the momentum-pitch space distribution of Runaway Electrons (REs) that impact the first wall are vital to understanding and mitigating the risks posed to future reactors from the intense and spatially localised heat fluxes of uncontrolled RE losses [1,2]. Direct measurements of the RE energy and pitch are challenging as they have so far relied on indirect measurements through modelling the observed synchrotron or bremsstrahlung [3,4] radiation, or using Cherenkov probes to determine the location and energies of the beam below 250keV [5]. On DIII-D, recent experiments using a dedicated sacrificial limiter were used to estimate the pitch angle and energy of REs during the final loss instability [3]. However, this scenario required the destruction of a sacrificial limiter for postmortem analysis to estimate the energy and pitch angle of electrons during a specific, well constrained event. Recent measurements made by the TCV Fast Ion Loss Detector (FILD) have been modelled using the Monte Carlo code Geant4, illustrating how the observed patterns on the scintillator correspond to the energy and pitch of REs lost to the first wall. Forward modelling of REs with pitch angle ratios of $p_{\parallel}/p=0.8$ and energies of $E=3$MeV interacting with the scintillator plate inside the FILD head are shown to reproduce two different kinds of spatial patterns observed experimentally. The results demonstrate the potential for direct measurements of the distribution of REs lost to the first wall using this novel detection methodology. [1] Boozer, A. H. et al (2017). Nucl. Fusion 57 056018. DOI: 10.1088/1741-4326/aa6355 [2] Matthews, G. F. et al. (2016). Phys. Scr. 014070. DOI: 10.1088/0031-8949/T167/1/014070 [3] Hollmann, E. M., et al. (2025). PPCF, 67(3). https://doi.org/10.1088/1361-6587/adb5b6 [4] Wijkamp, et al. (2021). Nucl. Fusion , 61(4). https://doi.org/10.1088/1741-4326/abe8af [5] Jakubowski, L., et al. (2010). Rev. Sci. Instr., 81(1). https://doi.org/10.1063/1.3280221