Potatoes are potatoes are potatoes. All spuds are the same. When they start popping up, keep banking the soil (lightly cover them and they will keep coming up. When they've got flowers on them, wait until they die, then pick them off. Because of the banked up soil (about a foot), use your hand and dig into the root of a bush and feel around until pull out a spud, if they are the size you need, then you can start digging up. I've got new potatoes which are not quite ready - I'm off on my holidays on Wednesday for two weeks, so they will certainly be ready when I get back.