Completely stuck in the top left corner.
8A Tool building in Scottish education course (4) - No letters, but it might be SHED.
10A Cuts laughter without hesitation (6) - ?????S
1D Loud and angry (10) - ?????A?O?E
2D One who tells you what's what (8) - ?????S?R
The 2nd & 4th letters of 1D are the 2nd letters of 8A & 10A. The 2nd & 4th letters of 2D are the 4th letters of 8A & 10A.