Planting for a very tricky site

Hi all, I have finally got around to digging out a small border at the front of our house. I'm interested to know what plants people would recommend. It's a west facing border, with a rock wall behind. It's in partial to full shade due a large problamtic sycamore. Which is 60-80 feet tall. The ground is therefore dry. My gardening style tends to be cottage style. Although I know this location rules out such of my favourites such as nepeta, digitalis and delphiniums. Some pictures below of the border and size of the tree/orientation 


Please ignore scaffold, we are havi g our roof done