I would start with where you want to deliver and work backwards as not all the Obs deliver at all the hospitals. If you want Matilda, go Lucy Lord or Grace Chueng as they are more likely to be able to get you in as I think, between them, they do something like 30% of all deliveries there. It sounds from your OP that you're intending to deliver privately, but just be aware that if you go to the public hospital for delivery, many of the private Obs won't do the ante-natal care.
I had Lucy. She is excellent, but she is busy, and to make her clinics run to time (the longest I ever had to wait past appt time was 20 mins) she is "to the point" so to patients who like to talk through everything at length, she might not be the first choice. However, in terms of the actual delivery I cannot fault her. I had a very positive birth experience.