This cryptic seems to be more cryptic than the norm. You should try to ignore any extra stuff.
Crypt-ish places are usually darker than this. D'EAUBONNE and the CHAIN BELT are useless here.
9-across is a clue for SLAV, plus the extra word "loo".
But a LAV is a loo, so let's correct the crossword by blacking out the square the S is in.
Some words need more than one letter removed, while some go unchanged.
The message you (dis)cover will give a thematic name.
P.S. - This
might help if you're more of a straight crossword fan.