I agree with Guy that "Mangled cry of pain making bun, perhaps" wouldn't be accepted even with the indicated DBE. An indirect anagram has several possibilities (here, YOWL? YELP? HOWL? WAIL?) and you'd have to go through a tedious trial-and-error process to solve the clue. This example is solvable as there aren't all that many possibilities, but an indirect anagram of a 4- or 5-letter bird, tree, city etc. would be a nightmare!
I don't have a problem with initial/final letter anagrams provided it's clearly indicated, though.