We discuss how linear polarisation measurements of cluster imbedded and background sources can be used to learn about galaxy cluster magnetic fields via their Faraday screen nature. For this purpose we employ a large range of cluster simulations of differing complexity. We compare Faraday rotation grids from synthetic observations to available data and make forecasts for observations by future instruments, such as the Square Kilometer Array. By applying Bayesian analysis methods we investigate how well cluster magnetic field properties can be inferred from prospective polarisation data. Furthermore, we make predictions about constraints that can be placed on the origin, amplification and evolution of galaxy cluster magnetic fields.