You're supposed to do it in spring, not now, but its up to you. If you've got lots of it around the garden, you could risk doing it now because you've plenty more to replace it with if it doesn't cope, but it might be fine. They tend to flop over more if they're not in full sun, so really they should be supported as they grow during the season to prevent this from happening, especially in a small space.

Thanks Bamboo. Will need to move it anyhow as Magnolia tree has grown a lot and sedum doesn't get enough sun now. Will do it now and see how it goes. If I divide it up in small clumps and find sunnier positions it is more likely to do better. Any suggestions for shade loving ground cover plants for under my magnolia? Thanks :)

Moss for underneath the magnolia?

Gee does most gardeners want to keep moss out of their garden! Amsterdam all the following would work...
Hebe pinguifolia ‘Pagei’
Pachysandra terminalis ‘Variegata’
Vinca minor ‘Atropurpurea’
Bergenia ‘Silberlicht’
Rubus tricolor
Be warned the Vinca can be a thug!

If you look closely at ground level,you may see new shoots emerging..there are some on mine already..so if you want to cut it back,if it's in the way,do so,then divide the new growth in the spring..or take a chance and do it now..it's a tough hardy plant..it has given a very cold night,so maybe when it's forecast to come milder again,later in the week would be better...Some of mine are quite large too,but I support them with canes and garden twine..the growth soon hides them in summer ...another alternative is to split one of your others in spring instead,and dig this one out...

No contest for me - I'd choose Campanula portenschlagiana (used to be C. muralis, still sold as that sometimes), but NOT C. carpatica or porscharskyana because they're messy growers. Flowers and a neat, speading, evergreen low growing ground cover which only needs the spent flower stems pulling or cutting off, what more could you want;-)) Otherwise, Lamium Beacon Silver or L. White Nancy.

Epimediums do well in shade under a tree and the leaves are attractive all year round. One yellow flowered variety (sorry I forget names) has wonderful spring foliage too, as well as dainty sprays of yellow flowers in early spring. You cut off the old leaves in early spring before the flowers appear and the gorgeous new ones quickly grow. Just one will make a large clump in a few years.

There are several ferns that will do well in dry shade too.

Thanks for all your suggestions. When I’ve got a moment I will dig this one out and quite like the purple campanula carpeting the ground underneath the magnolia tree. Will show you finished results when completed!

also consider some of the variegated and bronze leaved Ajuga. flower in spring too. Pachyphragma is anice spring flowering one too. I grow it in my shady part.