We bought this large (45 cm diameter) platter from a Melbourne auction house in 2005. It is decorated in muted tones in a triangular pattern using a glaze-over-glaze technique. The mark is an impressed M in an octagon. I don’t know anything else about the potter.
It must be challenging to throw a platter this large. It creates a relatively flat surface for decoration that brings out the painter in the potter. In this case, the ragged painterly edges of the triangular motifs and the transition from light to dark creates an interesting sense of movement within the bounds of the circular form.