1. African Institute for Mathematical Sciences, 6 Melrose Road, Muizenberg, 7945, Cape Town, South Africa
2. Institute for Astronomy, Royal Observatory, Edinburgh EH9 3HJ, UK
3. University of the Western Cape, Bellville, Cape Town 7535, South Africa
4. South African Astronomical Observatory, Observatory, Cape Town 7925, South Africa
5. SKA South Africa, The Park, Park Road, Pinelands, Cape Town 7405, South Africa
6. Department of Maths and Applied Maths, University of Cape Town, Cape Town 7701, South Africa