Do the beds get much overhead light or are they in the shadow of a wall or fence?
I planted my long, narrow north-facing bed in Herts this year with:
Skimmia, fatsia japonica, spotted laurel, euonymus, hellebores, heuchera (purple leaf), miniature fern, cyclamen and primula vulgaris (these were self seeded so I split them and distributed).
Everything has taken really well. I think they're all suited to north-facing beds but someone may correct me 
I'd recommend using a mixture of light, dark, variegated and golden greens, combining architectural shapes such as the fatsia japonica with bursts of colour at ground level (cyclamen and primula - you may get away with other bedding plants if the light is sufficient).
I thought I'd read on other threads that you can get away with planting in November as long as the ground isn't frozen or waterlogged. I don't know if it's ideal though. Maybe the plants need longer to establish their roots before the first frosts.
Like others I find the RHS website invaluable for cross-referencing. The plant fact sheets are excellent and tell you which aspect is best suited.
Does anyone know whether you can get away with planting tulip bulbs in north-facing beds?
If so that could be an option between the shrubs and you would have a nice spring display.