My Tropical Gardening book says to wait till the frost blackens the leaves (you don't have to though), then cut the foliage down to about 5 cm, lift, shake off excess soil and leave to dry out on newspaper in a dry, airy place. Then store in old orange boxes filled with dry bark chippings or peat and keep somewhere dry out of the frost.Check occasionally during winter and discard any rotted tubers.

I've never had an empty orange box, so I just used a large container filled with very dry, used potting soil. Either way, its a bit like storing dahlia tubers - keeping them dry is the most important thing so they don't rot, and somewhere they won't freeze.

Thanks Bamboo very interesting to know .

Yes I treat them like dahlia tubers. Knock of the old compost allow to dry and then I put them in a large pot and I use sawdust instead of compost but the principle is the same. They then go in the shed.

Thanks Seaburngirl