Have a look at this page
(scroll down to Width Considerations).
The table doesn't list 14mm rims but reading between the lines, 28mm will be fine and 32mm should be fine too; as Sheldon says, he errs on the side of caution.
Thanks for that, some excellent information. The rims are a bit odd, the external width is about 20mm but the clincher 'lip' is quite thick, giving a minimum internal width of about 14mm, underneath the lip the width broadens out to prob 16 or 17mm, took some advice from the LBS and they said the same as Sheldon's site, running 28's or 32's on these rims would be fine. Happy Chappy:D