Lifting the plant was easy, and didn't even require a fork - I simply grabbed the bunch of stalks and pulled, then rooted around for the tubers. There were a number of small pinkish white tubers near the surface which will be used for replanting (I have stored them in a bucket with just damp coir peat), and one I planted out just to see if it will manage to grow back.
Of the edible brown tubers, they were of a good size. Approximately a third of them were rotten - it would be interesting to try to harvest slightly earlier next year to see if I can get a better yield. Note, I had tried to harvest a different plant in another location a month ago, and there was nothing there to harvest, so it is probably worth waiting for the soil to heave and at least some of the stalks to die back.
I placed some in the sun for a day, and have stored in the fridge crisper in a plastic bag.
The plan is to cook these in a hotpot - they absorb flavours well but add a sweetness to the dish.
Update (26 June). Checked the yacon plants in the banana circle. The plants themselves grew well, but they produced no edible tubers. The harvest referred to above were simply in the ground (next to Panama Berry tree). I surmise that the difference is moisture - the banana circle is quite a moist area, whereas the area next to the Panama Berry is reasonably dry.
