Regarding the discussion above - I have just been to to the C&J store and they actually think that the RL tassel is not made on the same last as the Cavendish which would explain the different fit..
In any case the shoes are now with C&J and they are trying to figure out what they can do to improve the fit. Hey had initially suggested that they could "re-last" it on the 325 but I think they now said that this was not possible. I will report back with their proposed solution ..