Some of the seed companies sell tubers which have been kept in cold store to enable a late crop to be grown.
The warning I'd give you is that they often don't do very well as they are growing at a time when blight becomes very prevalent. Your best bet would be to grow them under cover. Tubers you have just harvested are unlikely to sprout in time to be grown so you need some tubers kept back from the ones planted in spring. You could try keeping these in a very cool place to retard the growth of shoots.