QF refer to T1 to T3 as seamless lite (international to domestic landside)
There in lies the problem, maybe financial had a part in it, for them closing their xray and BP printing processing at SYD T1, maybe too that SYD airport wanted that spot back, and QF agreed, saving money and human resources.
In the past, we could easily get from T1 to T3 on the secure side, after having xray at T1, but now, after the change, they drop you off outside T3 on the open public side, and you have to go dom xray with everyone else, no "special treatment" anymore.
They might call it seamless light, (edit: "lite", going US now, more like problem in the prosterior side.
Not that QF would admit it.
Going from T3 to T1, yes, that one is easy.
And Franky got there just at the right time, as the bus was already full, and I have used it full too, they tend to wait till the bus gets full before moving off, not so much on a schedule.
And packed like a sardine can it is too, not only humans, but also their HLO, that would fit into overhead lockers, but still quite big and large and bulky for the bus..