Just to provide a useful response to the OP rather then useless drivel, while 6mm would probably satisfy your load and may technically be safe as the upstream OCPD would operate before the cable could become overloaded.
Convention and possible a regulation somewhere would say that 16 or 25mm tails would be the preferred cables to use in this scenario, 16mm would be more then adequate, the idea of splitting the tails into a sub CU is also very sensible
Convention and possible a regulation somewhere would say that 16 or 25mm tails would be the preferred cables to use in this scenario, 16mm would be more then adequate, the idea of splitting the tails into a sub CU is also very sensible