Just about time, and PR is up, so:
Thanks to all for the usual set of inventive clues that make judging such torture (but only in the most positive sense of that word).
There were many clues that played on "keep", as well as "the French" and either anagrams or "caste" with one letter inserted. Although these were all very nice, I can find no reason to say that one is a lot better than any other. If forced to pick the ones from this bunch I liked best: jono@8 and fiona@26 for the nice surfaces.
Hono(u)rable mentions go to:
paul@30, although I would have preferred Civil Engineer for CE, since that's one of the things civil engineers actually do. Unless a war criminal was holed up in the chateau, in which case the clue is fantastic.
jono@19, love the wordplay, although I am hard pressed to think of a scenario in which the surface makes sense. Tic-tac-toe, maybe?
pat@25 for getting Ethel back into the mix; my only quibble being that you can cast someone without it being the lead role. I accept that this is being picky.
pat@28, nice charade, although as a native Chicagoan, I have to point out that no one who lives in a mansion rides the el.
jono@39 and bbm@49 had nice subtractive anagrams. jono's had the better surface but was missing an anagrind for what's removed, since it was removed in pieces (I understand that's debatable, but this is the hill I choose to die on). bbm had the anagrind but as far as I can tell the story of Lancelot and Joyous Gard is lion-free, so the surface did not work quite as well.
My final decision comes down to two clues:
pat@10: Perhaps Chillingham cows get sun for the first time (6)
Clever wordplay, nice surface, and the amount of research that went into "Chillingham" deserves some sort of special commendation all by itself, the Ordre de mérite des mots croisés perhaps.
paul@42: Stuck on the side until swapping positions with senior member on board (6)
I normally don't care for cryptic definitions, but this one really struck my fancy with the beautifully misleading surface. And after all is not the world of business much like a chess game? Pawns and all. Therefore the gold goes to paul@42:
Stuck on the side until swapping positions with senior member on board (6)[\b]
Nice one paul (and welcome to fiona!)
To the prizes:
One for the chess fans:
https://www.youtube.com/watch?v=iAv2dG_RDWo
One for the tourists:
https://www.youtube.com/watch?v=4zewU-fMQ50
Music bonus (contains the word "castles", anyway, and is awesome):
https://www.youtube.com/watch?v=t4sK8d48Exs