Hmm, bit restricted in winter, that kind of situation. The classic front door pots are Bay and Box, but both suffer a bit in cold wind in winter. If you like conifers, though, not a problem, but be careful which variety you choose - some suffer windburn. Ones that cope well in cold, northerly, exposed situations are the following varieties (but obviously, choose a dwarf variety) Chamaecyparis; Cupressus; Juniper; Pinus (pine); Thuja and Tsuga.

My front door is north facing, but very sheltered. I have Box in various shapes in glazed pots (balls and pyramid). I also have 2 types of Christmas Box (Sarcococca - the common one and a purple stem one). All survive with the low direct light they get. The Christmas box is for scent in winter.

Holly does fine and you can topiary/prune that into shape.

If you have space, then I think a zinc planter with Hellebore or Japanese Anemone in it looks good all year long.

Skimmia is quite slow growing and would probably be OK for a number of years. Black Knight is attractive but male - if you have only one pot and want berries go for a self fertile variety - sorry i can't remember the name. And use ericaceous compost if you have any.

Heather is another option if you don't have much space.

Or heucheras of course

How about Ivy trained on wire frames, if you want something formal and 'front door-ish'. I also have Photinia doing well in a north-east facing spot, you could try standards of that, available in GCs. If you want something bigger, my Leycesteria is in a pot in a fully shady part of the garden and seems not to mind too much, although it might not like a very windy spot. Oh and that lovely stalwart...prunus laurocerasus does fine in shade as well and it's evergreen, and you can prune it hard or topiarise it. I wonder if some hollies might also be ok there.....not sure, but mine are doing fine in total shade all winter long. I'm also wondering about Rhododendrons.....they tolerate shade well, but you need ericaceous compost of course. I love a challenge, hope you find something you like! :)

oooh, just remembered , Sarcococca...lovely scent in the winter and mine is in full shade and thriving. :)

Thanks everyone for such helpful replies. I am hitting the books with your answers in front of me and can then make a decision with my chief gardener aka husband. Like the idea of the zinc planter as we have just painted the door a light blue. Will post photo when decision made!

Bit more advice - if the container is metal, including zinc, line the inside with something warm - that warm, thin packing material made from flexible polystyrene is perfect. This helps to insulate the roots, which are more vulnerable in a metal container. Also bear in mind when making your choice, that plants which may do perfectly well in the ground in northerly exposed positions may not do well with their roots in pots - they're more vulnerable to frost/freezing.