Now my ag. science based disease freak of a mate (the stats! guy) - goes apoplectic about the above - disease, disease, disease.
Given that this challenge is getting serious, I discarded my hippy ways and went down a bit of a serious gardener path this year with potatoes. I have two plots. One in a big black tube - going for a bit of additional vertical height. The other - dug rows like you will see in any standard garden book.
So.. the challenge? Here is what I just pulled up from my very small feral spud zone. (no sticking these in the summer storage zone!)

2 ltr ice-cream container.
If my attempt at the serious gardener approach can beat that, then I will eat well. If not, then .... I'm buggered and in the future will be sticking to my tried and tested technique...