12a Didn't it fall upon Isaac's head by the will of God .... (5) ?P?R?
20a They keep us guessing under fleeting over-sights (4) ?F?S
28a Gunners at the top of their game? (4,2,4) ?A?G?N????
27d Looks like a cave dweller peeps up to take a stroll (4) T???
24d This one's down to footslog (5) ?R???