Aucuba does well in this situation, good in containers, and the lovely foliage brightens up a shady area, i also have brunnera [jack frost] in pots lovely silvery green foliage with blue flowers now similer to forget me nots, and you have plenty of choice whth all the different hostas you could choose, azales/ rhodis are ideal so long as its not dense shade.

Epimedium is one of the best plants for shade . . . many varieties, some with bronze leaves; grown for foliage colour rather than flowers which are tiny. You could also grow Violas, Primulas and Honesty for colour.

Fatsia Japonica is fabulous, but it does need a large pot.

Fatsia japonica does not need a pot - they are hardy and best in the ground.

I think Melchisedec meant if it is to be in a pot Fatsia japonica will need a big one.
Ferns grow well in a shady (s)pot, Ivies of course soften the edges of pots, bugle soon covers the soil surface (I particularly like the variegated one), dwarf conifers may be used to add height, alchemilla mollis looks lovely after a shower, , and bleeding heart has attractive foliage and distinctive shaped flowers which are very pretty in Spring. Cranesbill could be pot-grown too, I'm sure. These last three take a well earned rest during the winter, but snowdrops and early dwarf daffs/narcissi and maybe cyclamen would fill the gap in late winter.

Box, fuschias, lilies & herbs are all good in pots too.

Christmas box does well in shade and has wonderfulLy scented flowers in JANUARY.

Thank you everyone for your very helpful advice. Much appreciated. x