My all time favourite bold foliage plant for shade is Fatsia japonica. We quite often see these as small shrubs. Their average size is about 1m tall and wide in five years. However, they have potential to grow larger in time and one of my clients in Northamptonshire has an impressive specimen 4 metres or taller growing up the side wall. Absolutely glorious! A Fatsia japonica could be complemented by a smaller leaved shrub such as Osmanthus delavayi. This is a slow grower and can be restricted in size by pruning if necessary. It will have small scented white flowers in late spring. An underplanting of bergenias would look superb. These will have spring flowers but their real benefit is their wonderful bold leaves which will often change colour in winter. Pop some snowdrops around them for a real touch of class.
Skimmias and evergreen viburnums will also grow well in shade. Perhaps contrast rounded Viburnum davidii's with an upright spiky Mahonia x media 'Charity'. These will have fragrant yellow flowers in winter. Underplant with muscari bulbs or Ajuga reptans.
Acanthus mollis will also grow in a shady spot. Although the flowers will be few the architectural foliage will make a good show. Euphorbias - another classic foliage plant prefer some sun but will tolerate shade. Use Euphorbia amygdaloides var robbiae if shade is a real problem. Don't forget the many beautiful varieties of Hedera (ivy) if you have walls to cover. Evergreen Euonymus will also climb walls in time and will thrive in part shade. Other ground cover plants for shade are the Vincas (blue flowers) Alchemilla mollis (deciduous with yellow flowers) and Pachysandra termanalis (white flowers). My personal favourites have to be the hardy geraniums like Geranium macrorrhizum but they are deciduous and their foliage may not be bold enough for what Sarah is trying to achieve.
Other classy combinations for a small courtyard are hostas and acers or maybe Sarah could try bamboos and ferns. As a fellow designer I'm sure that she will remember the golden rule of keeping it simple. Repetition using a small number of varieties will give the best effect. If you would like to see some of Sarah's interior work her web site is www.charlottedesigns.co.uk