Plants should be lifted in the autumn, after flowering, and any soil cleaned from the roots. Cut top growth down to around 15cm (6"). It does no harm to dip the root ball in a disinfectant, such as Jeyes Fluid, for a few minutes to maintain cleanliness. Some growers also use a hot water dip to control eelworm. The recommended treatment is five minutes in water at 46°C (114°F). After this, dry the stools thoroughly, trim the roots to about 15cm (6") in length and then box them in seed trays using an open compost. Store in an airy place (a cold greenhouse is fine) and keep the compost dry. Plants grown in pots can be moved into a cold greenhouse, or some other sheltered place and, as above, kept dry.
So if they have finished then do it about now.

Thank you some are ready