The result of the 2.5/1.5m scenario is about 0.5m from the deck. So it probably would be fine. But that’s just from yours and my discussion, which means nothing to the guy that actually bolted the climb. It’s his decision.
But like the other guy said, it’s probably not best to compare somewhere like Churchies which is an older crag and mostly produced before the climbing explosion. You know, “back in the day”? Western Australian climbers seemed to have a ‘hardman’ mentality of outdoing each other with their daring. And it still continues today to a lesser extent. WA climbs haven’t been done the way the rest of the world did it, ie. make the outdoors conform to how indoors works. WA climbs began with whoever had the biggest brassies! Maybe there should be a bit on the website about some of the stuff they used to do… like practising body belaying by tying into drums and chucking them off the top of quarry walls!
On the other hand, how does Mountain Quarry compare? i haven’t been there in donkeys and there’s been quite a bit of work done since. As such it contains the greatest concentration of sport climbs. Which is what you’re talking about, right? Whereas Churchies is mostly a trad crag.
Otherwise my other comment still stands. If it exceeds your risk tolerance, don’t do it. There are plenty of other climbs.