When they've finished flowering and died back. So probably spring.

Difficult with some of them as they do not go dormant until May. As said, wait ntil the leaves have gone then move them.

These are probably Cyclamen hederifolium, given the wonderfully large corms. I rarely get to move any but understood that the 'best' time is just before they come back into growth again, say July/August. Trouble is you never can tell. Some of ours never seem to go to sleep propery.