I use both the Axminster SK 114 (114mm) and the Axminster Clubman 100 (100mm).  They are excellent chucks.  I prefer the SK114 because of the wide variety of quick change jaws.  They are available through Woodturning Store, Deer Park, NY.  Axminster has a good website where you can explore the wide variety of jaws for both chucks.  I believe the website will refer you to their US dealer mentioned above.