In these proceedings we present an exact distillation setup with stabilised Wilson fermions at the SU(3) flavour symmetric point utilising the flexibility of the Grid and Hadrons software libraries. This work is a stepping stone towards a non-perturbative investigation of hadronic D-decays, for which one needs to control the multi-hadron final states. As a first step we study two-to-two s-wave scattering of pseudoscalar mesons. In particular we examine the reliability of the extraction of finite-volume energies as a function of the number of eigenvectors of the gauge-covariant Laplacian entering our distillation setup.