FWIW I don't mind a bit of flaming - it's expected on forums. I'm comfortable with my analysis and whilst I'm not happy with my pre-crash thinking (over-confident) I'm happy with both the bike and, apart from speed, my riding decisions.
1. Entry speed - look, truth be told it was probably more like 70-80km/h than 60km/h. The 45km/h sign should have been the warning, as from the top of the hill it looks a glorious left-hand sweeper so the thought does flash through your mind as to "why is it posted so slow?". Of course I ignored that flashing light bulb and was going at what I thought was a manageable speed for the corner, but you can't see the mid-corner road damage until you are right on it. It's then you realise why it is posted at 45km/h....... This road has been is used for plenty of closed-road car rallies - and this is the corner which apparently creates many race car crashes - and road accidents as well. It simply looks a lot faster than it is, and reinforces that since I didn't know the road so should have been erring on the side of caution, posted signs or not.
http://www.supersymmetry.com.au/GPz/photo1web.jpg2. Suspension - It's effectively a mid-corner spoon drain, so as far as I understand (and from watching the cars go through it) the suspension physics are the same - as you enter the dip the springs slightly expand, then they compress as they come up the other side of the dip, and then the suspension rebounds. I don't think any bike of any generation is going to like that mid-corner. BTW the bike has a virtually brand-new Hagon rear shock installed, and I'm not convinced that the "old" suspension has got anything to do with it, but I'm open to technical discussions (apart from lower sprung weight & tyre advances which are obvious modern advances) as to how & why newer bikes might handle this scenario better.
Thanks to everyone for contributing, as mentioned I now understand why it was the rear that went not the front. The mental transition from cars to bikes was actually a lot harder than I thought, so in a way this was a crash I needed to have - it has instantly made me a far, far better rider because now (hopefully) I will be thinking like a bike rider - not a car driver. And whilst I acknowledge that the standard GPz rim/tyre should have more than sufficient grip, I'm 99% sure I will proceed with the zzr600 rear rim upgrade as I need to get another rim/tyre anyway, and the extra 28% of rim width (plus grippier tyre options) is kinda comforting....
http://gpzrear.blogspot.com.au/2013/07/1-17-rear-wheel-conversion-for-gpz900r.html