[SOLVED] Favicon doesn't want to appear or doesn't do so properly

I've replaced the favicon file in my icons directory and set the ATO option to point to the (now only) image in that directory. But it isn't showing up on the tab in Firefox.

The path is www.executive-post.info. I've tried the same in another domain and the same problem exists. I have refreshed the cache in both cases.

Any thoughts on what else I can try, please?

Many thanks, Graham.