I just can't get these...
19d. Fellow apt to cheat at golf? (3) - D?G
21a. More than one change? (5) - ??NER (The 2nd letter of 19d is the 2nd letter of this)
21d. Where many a caber has been tossed (7) - ?RAE?A? (Obviously the 1st letter of this is also the 1st letter of 21a)