5 and 12a - A Scots poet - not Burns! (7,6) - last word ends in m - sorry no more letters
11a - quaking Sadanao is an ancient bard (3-4) - a?? ???a
13a - hurt his head with branch (4) - h???
14a - Scot hammers stake into ground (5) - ?t???
15a - Male is Mainwaring by the sound of it (4) - ???n
18a - Yes, with lots of ticker movement (7) - s???o?e