Next year I'm going to dig the plants up - whole - as soon as they stop growing sideways - and clamp them. Hopefully they will be big enough to try this in September.
I found in 2014 that if you gather the entire plants and bury them, the haulms continue to drive growth in the tubers even without sunlight. Unfortunately that time the pests found them even though I clamped them in a new bed (the
pests that spend Sept/Oct drilling 1mm holes in them).
This time I will lay them out and give them a bit of a clean with the hose before clamping the whole lot in something fresh - fresh compost from the bin or 'freshly' rotted woodchip from my spade-deep woodchip paths. I might use a builders bag for further isolation from the soil pests.
It would be a shame to have to grow them in pots, and my builderbag beds are too precious for anything except carrots and tuberous peas...
Cheers.