Lee provides fantastic customer service. My wife bought me a filter (as a present) which was a duplicate of one I already had. I rang Lee's UK operation and explained what had happened and they happily exchanged it for one I really wanted (top half 0.9 hard ND, bottom half 81B warm up).
I was also looking for a wide angle holder for a lens with a 95mm filter thread. Lee makes one but it will vignette. The chap at Lee told me they get round this by producing a 'push-on' version with a 100mm diameter and a 'shim' that fits snugly onto the lens. Their products aren't cheap but, in my experience, they are the best.