The single Minoura saddle mount cage holders will not work on a Brooks Swift. The rails are too far apart to get a good grip with the holder. Don't think it would work on the B17 either, but I am not positive (never tried, just looked at a B17 at my LBS, and the rail placement seemed to be the same). This is the one I have:
http://www.google.com/products/catal...d=0CF0Q8wIwBA#