I think I have finished but am unsure about 4 answers.
9 across.Clue is:King is winning with a knight's intervention.Is it Canute?
11 down.Clue is:Working for exam success,being way below the level of others making progress.Is it underpass?
37 across.Clue is:Island rescuers on road caught boy almost meeting early death.I have I?A?C.Is it Isaac?
52 down.Clue is:Scot expelling English from a port.I have A?G?S.Is it Angus?
Any help with answers and explanations much appreciated.