I didn't even know there was a Yayoi in Chatswood until a friend recommended. There was a 24/7 one in the neighbourhood I stayed in Tokyo but ironically, I never had the time (or stomach space) to go there even though it opened throughout the night. It's a good place to go if you want your own meal since this sort of stuff is hard to share.
I didn't feel like the whole set meal even though it's probably more value for money compared to the udon as I was still full from earlier in the day. I think it is a bit pricey for a bowl of udon, and not that much meat. The soup wasn't overly salty that you're reaching for water all the time. The actual udon was average, nothing special in terms of texture.