UV
You aren't really out of pocket. You may not have made it to France, but you would have paid slightly more to land at Le2K than you did at Lydd, so what's the difference.
I don't really regard this as a weather diversion. I flew in Kent yesterday and CAVOK could not describe it. 40 mile vis, zero cloud, VRB <10kts.
In the circumstances, you can understand why you should have to pay the same as the people that intended to fly to Lydd.
By the way, they have a good restaurant and are a short walk away from a wonderful beach, which is on "La Manche".
I have posted the terminal phone number on another forum and they will give you a TAF, of sorts, if you ring them.
Hope you still enjoyed your day.