SJ I understand your worry! But take comfort in the fact that all was perfectly well at your checkup. By the way...

I'm not sure if this is an option for you, SJ, but given your worry, do you think you could pop in and see your GP and get a referral for a scan?
I'm not sure if you would have to pay for it, but your GP could request that they bulk bill and that it is necessary to check out placenta function.
It might be just what you need to keep your mind at rest.
In saying that, I am sure your baby is absolutely fine from what you've reported - lots of movements, your good BP & generally good health, I would think bubs is perfectly healthy and is just needing a little extra baking time.
But go for the scan if you think you need it.
ETA: Snap, Spice
There is a place in Toowong that does bulk billed scans, it's on Coro drive just past the blue tower at toowong (i.e. closer to the city) called x radiology.

I hope you don't need the scan though and things start happening for you naturally in the next few days. Sending you labour vibes!