Many people have helped with information: I am particularly grateful to Ian Benjamin, Richard Chase, Tony Chase, Al Colley, Chris Daley, Pat Gray, Frank Hartley, Chris Hillman, Anne Hobbs, Keith Pitchforth, James Rosling, Patricia Struthers, Eileen Thicke and Marjorie Wray for their contributions.

I have also benefited from family trees published on the Web, especially: 

Stevens