7a man in temple produces cereal (5) - *h*a*t - presumably 'wheat' but why, apart from 'he' in the middle? 3d retreat below, hard to port (7) - *a**ou* - is it 'backout', but if so why? 19d loudly made a hole in plank (5) - *o*r* - 'is it 'board'? 16a thin line inserted into transmitter (7) - *l*n*e* ????