First, a word about the pyracantha - it might be that, as it puts on growth during the season, anything growing in front of it is not actually trying to reach light, but rather trying to get away from the overhanging or over reaching pyracantha, so keep that trimmed well back.

If its mostly in shade, but you have, say, 3 feet of clear space between the pyracantha and the front of the border, then there are smaller shrubs you can use. Flowers are much more difficult, so here's a few shrubs that won't mind those conditions at all: Skimmia (you need male and female if you want berries, but check out Magic Marlot, its a delight on its own anyway), Sarcococca varieties, Prunus laurocerasus 'Otto Luyken' (not the other large cultivars, this one only gets about 3 feet high and wide), Mahonia aquifolium, though you may eventually need to keep it trimmed back from the edge of the border, and Pieris forrestii varieties. Euonymus fortunei varieties are certainly worth a try - Euonymus pierrolino might tolerate the shade, and Euonymus Green'nGold certainly should do. As for flowers, Fuchsia, provided you don't allow it to dry out too much in summer; Fuchsia genii has yellow leaves, stands out in shade, or Madame Cornelissen with pink and white flowers, both hardy, otherwise Japanese anemone, Alchemilla mollis, Lysimachia punctata varieties (can be invasive), Campanula muralis, Campanula persicifolia, Digitalis (Foxgloves), Lamium maculatum varieties such as 'White Nancy' or 'Beacon Silver', Heuchera varieties, including Heuchera Red Spangles, grown for its red flowers rather than its leaf colour, and the ubiquitous Geraniums such as G. 'Wargrave's Pink'.

Dear Bamboo,

Thank you so very much for going to all this trouble. I greatly appreciate your comprehensive suggestions and expertise. Some of these plants I have tried in the past, with temporary success, but have usually been defeated by my own ignorance as much as the conditions in the garden, and the elements. I will explore your ideas, and hopefully get re-planting in the autumn. I feel quite excited at the prospect of something new happening for next year. Thank you again.
Linda

I don't know what you think you got wrong, but to be honest, the usual problem is watering - not enough nor often enough in the first two years....

I would second the vote for Heucheras, and I'd also cram in as many Cyclamen hederifolium as I could afford, because they'll give pretty ground-cover leaves all winter, before the spring bulbs come up.

Thank you Teadrinker. Your garden sounds challenging but gorgeous. And thanks for the watering tip, Bamboo. Much appreciated. Linda