last third-need a push 2d make for the box,inserting a key 6 C?????casket? 15a in every possible way,you add,a friend to 7 ?o?A??? 21a guided back to find heaped outside 7?I???N? distant? 11d speculator who got one on to gold 7?U????? thanks
Friendly tip: enter nothing in the grid unless you can explain the presence of every word in the clue. Guesses will just mislead as cross-checking letters will obviously be wrong.