In your relatively cool maritime climate you might be able to grow the same Pansies (Viola x wittrockiana) year-round and even have them last for more than a year, though they are bred and treated as annuals nowadays. Also try Bedding Violas (Viola x williamsiana), the flowers are smaller, but more numerous and I find they display better and recover from being rained down better than the larger pansies. They have also been bred to show an even wider range of colours and patterns. Think of them like annual orchids.
In my climate, with hot summers, Violas and Pansies do best as cool-season annuals, to be replaced in late Spring with warm-season annuals such as Impatiens, Madagascar Periwinkle (Catharanthus), Petunia, Marigolds (Tagetes), Zinnia, and others.
