Okay, I've been wracking what little brain I have long enough!
57a. E---E-- ,English cathedral shorly engages say a scriptual interpreter (7)
43d. -U-B-I-- ,Puzzle, say, is where in the middle to make ship bigger (9)
45d. N-T-R-- ,Turn up wearing tie outside royal place of entertainment (7)
The last letter of 43=last of 57
The last letter of 45= 3rd of 57
45d