This spreadsheet contains the data used to produce Figure 4 of the paper. All the results were generated with the finite element simulation code COMSOL Multiphysics 6.3 and refer to the nested fibre structure shown in Figure 1(c) of the paper. The spreadsheet has three tabs that contain the data for: (i) panels (a) and (d); (ii) panels (b) and (e); (iii) panels (c) and (f) respectively.