Flowering bush in the Paddock by the duck pond, Emmanuel College, Cambridge, England

I’ve spent ages searching Google to try and identify this flowering bush, but I’m no nearer the answer. Maybe it’s time I invested in a decent plant book. Cambridge colleges, though, seem to specialise in rare plants, so I’m not convinced I will find answers. In the background is the duck pond and Emmanuel hostel of Emmanuel College, Cambridge.

Edit: In Jesus College, all the trees and plants are carefully labelled. This is a garrya elliptica (silk-tassel bush).