Aha! I've often wondered what those little flowers are. I initially mistook them for elderflower before I had a sniff :)
I know the cotoneaster family encompasses a wide variety, but I've never seen one that looks remotely like this - either the flowers or the leaves! Our varieties have smaller, rounded, waxy shiny leaves and tiny individual flowers along branches. I've had both the low ground spreaders and the shrub variety and love them both. Very good in our dry climate, winter and summer.