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In this study, a detailed survey has been made of 200 silicon carbide crystals grown by the modified Lely technique. All 200 crystals were examined using, at minimum, the combination of X-ray oscillation photography and one synchrotron topograph. This has now produced a reliable and unique database on polytypism, one-dimensional disorder, defect content, and in particular their spatial relationships. Over half (114) the crystals were multi-polytypic, some 37 displaying complex polytype combinations of which 16 included a long-period phase. For some 32 crystals, where shape and size permitted, synchrotron edge-reflection topographs could be obtained leading to depth profile models of the polytype content; 9 of these have shown up a very interesting class of configuration, the idealised form being termed a ‘sandwich’ in which a longer-period polytype layer inside the crystal is surrounded each side by …