Bar one, all the plants are gone.  The one lonely straggler is the raspberry bush, which I am hoping will survive.  All of the others were past it, and I decided it was better to start anew.

The question is, is it worth it?  It is mid summer here now, and although it is Queensland, the temperatures will start dropping in another month or two.  Also, the garden is still particularly alkaline - I also did a test on the rainwater, which matched! - and I would need to do something to fix that.  Apparently it is difficult to change the pH of soil which has free lime / chalk in it.  The test to see whether this is the case, is to take some soil, add vinegar to it, and see whether it fizzes.  It did.  Apparently free lime buffers the pH of the soil and defies all attempts to fix it. 

The only viable option I can see is to add elemental sulphur to the soil, which should activate in 4 - 6 weeks, and then retest to see whether it did anything.  Then, perhaps I will start planting again...