With the object of explaining the anomalous losses observed in thin ferromagnetic sheet, several authors have calculated those in an idealised material containing regularly spaced domain walls extending right through the sheet. These calculations are now extended, firstly to yield analytic expressions for the real and imaginary parts of the permeability which facilitate comparison of the theory with experiment, and secondly to include the effect of variable wall spacing, and stiffness. Extensions to include spin phenomena are also discussed.