Cool. Winter interest plants are going to be the toughest. At least you can do things to attract birds in winter, which everyone loves. In summer it's easy... Anything that fruits or flowers will do the trick.

Two more winter plants that do great in England, are Red bark Dogwood and Pyracantha, although I have to warn that the latter has woody thorns, so you might want to plant that away from the path. They do do great in espalier form though, so it wont take too much space.

Edit. Just reading a bit more about it, there seems to be one of the Pyracantha family that is thornless, called a Cotoneaster. I do not have any experience with it, however.