[en] Full text: Recent progress in the theoretical modelling of the effects of plasma pressure on the growth and change in geometry of magnetic islands in the H-1NF Heliac will be reviewed. The HINT magnetohydrodynamic equilibrium code, which has become a standard workhorse in the stellarator community for problems of this type, has been modified to incorporate an interpolation algorithm which significantly accelerates its convergence. This has enabled the critical evaluation of earlier results, and of some conventional wisdom. In many ways the treatment of magnetic islands in low shear fusion reactors, such as H-1NF, is an ideal case study in computational science - the devil is in the details and the devil is important: the existence or otherwise of island self-healing at reactor pressures could significantly affect the design of future experiments. (author)