STEREO A/B L3 GP inversions (Krupar et al. 2022) overlaid on Fig. 8a. The GP points show a clear trend in agreement with BELLA in both orientation and frequency distribution (as indicated by the colour scales). The GP results have a larger spread and make interpretation of an underlying spiral more difficult. All localisation methods are shown to be in agreement, illustrating that complementary but independent methods give approximately the same answer, which further validates the BELLA methodology.