Another plant puzzle

This is a big bush, deciduous, 2m high and 3m wide. It used to be in shade under a big loquat; though it seems to be flourishing without the shade. 
It's at least 20 years old, too. Planted by my predecessors in this garden.
Any suggestions ?

Thank you all for the stars and comments on yesterday's Blipday. I enjoy the little bits of insight into everyone's perspectives.