My personal opinion is that there is nothing quite like it. The closest in my wardrobe are either too little (Hermès Eau de Pamplemousse Rose) or too much (Domenico Caraceni 1913). I can't sign onto Prelude to Love, even though I respect DULLAH's opinion greatly. To me, Kilian's style is so glossy and rich, that it removes it from being anywhere in the proximity of Windsor, which is more natural, humid, and "matte finish" in texture. That is where I cite the Hermès. It has that aspect of Windsor.
And then there is the eucalyptus. Where else are you going to find that? I'm completely disregarding that in looking for something close, because if you leave that in as a requirement, then there is almost certainly NOTHING that smells like Windsor.