I was just going to ask the exact same question! Calais is really nice, and I think I paid €12 last time I went (about 2 months ago in an Arrow).
Still think it a big shame that we can't clear customs anywhere near Paris, I am starting to take a dislike to these unwanted stops on the coast. It was fun the first few times, as you land at different places that did customs, but now there are only a few, and I've been to all of the usual suspects.... I doubt that with Brexit it'll make it any easier either.....