Fleur, I'm about to attempt the same myself, for the first time :) I did lift several plants that had been in the ground about a year a while back, amended and enlarged the bed, then put them back within a couple of days and it was summer - those never skipped a beat.
Now, I have many large clumps I want to move from a house I'm listing for sale, contemplating dividing and possibly leaving or sharing some divisions.

From my favorite plantsman, Dan Hinkley (of the former not current Heronswood) says, "Divide hellebores in late winter or early spring when they're in bloom. Begin by cutting off the flowers with a garden pruner. Dig the plant out of the ground, and use a knife to cut the root ball into two, and then into four; be sure to always include part of the center root. Plant the divisions in the garden immediately unless the roots are very small. If that's the case, plant the hellebore in a pot for one year, so it can re-establish its roots. "

So, cutting off the flowers when in my mild climate they will last well into late Spring would be difficult - I'm on the fence with that one, although questioning Dan isn't something I readily do.

From possibly my second favorite plantsman - Tony Avent, "The ideal time to divide is during the fall or winter, although it is also possible to divide plants around flowering time. Clumps can be lifted, divided and reset or can be divided while in the ground using a sharp knife or shovel. I don't recommend dividing them to single divisions, which is rarely successful."

Thanks. If Hinkley and Avent say it's OK, I guess it's safe to dig now.

Seedlings have taken over and grown to nice bloomers but way too many of them so am going to start digging. Hopefully, I can find a home for some of them or move them around the yard. Really need to stop these multiple births.

Have you taken the plunge yet fleur? I have been lifting and either potting or moving blooming sized hellebores for the last 2 springs. I've been amazed at how well they have taken this abuse. They hold onto their blooms and keep right on going. I spoke with a women who sells plants from her gardens and she advized me to lift and divide while they were in boom so I could see what I was cutting apart. Personally, I am trying to separate out plants I want to keep from plants I am willing to part with, and the easiest time is when I can see the blooms. So, I cut off last year's leaves and lift them with a digging fork and have not had any problems. In fact, I sold several to a local nursery and auctioned off a few at a garden club as a fund raiser, so they all looked good within days of being lifted from their garden beds.