I've already spent two hours on this and still got nine left. It seems exceptionally difficult this month.
16D Semi-Christian sect apt to leave Anabaptists confused (8) ?S?B????
I think it must be ISABANTS, which is an anagram of ANABAPTIST with APT missing, but I can find no reference to such a sect anywhere on the wibble thingy. Am I on the right track?