Polly, thanks, most appreciated. A double clue then? Z=END (lasts) ZEN+D (for daft), finally got it in my thick head. i don't get ZEND meaning bible but I suppose it must do somewhere in the craters of Mars. Idealism still buggeth me as regards solution. Ah the thing that plague you on a Sunday.
I don't have this crossword but I've found this definition of Zend in Chambers - it's another name for the Avesta which is the Zoroastrian holy scriptures, so a type of bible.