Not sure I understand one letter of the final grid - appears to be one letter based on original clues regarding bread and another regarding the final grid solution. Are you supposed to remove part of the letter to give the other letter?
There is a weekly Listener thread on here, but the regular contributors have an unwritten rule not to answer any specific clues, although you may get someone to give a hint.
Here's last week's thread, but don't think it will shed any light on your conundrum.
I'm away from home and don't have the puzzle with me. If you could give me a little more information I might be able to help.
The 'bread' clue I can remember involves Yorkshire dialect (from 'Ilkley moor...') where the word for 'without' is the same as the currency of Thailand (4 letters).
I can't remember there being any letter changes for the final grid, but there's a missing letter to be added to form a plural (and it isn't verified in Chambers).
Ive had another look at the puzzle clues/blank grid and here's another 4 letter 'bread' answer (the edible kind) that removes 'th[e]' from a biblical prophet, is that the one?
I still have an issue with one square which seems to need a change to the original letter - or is this just removing part of the letter to form the other? Other than that a very enjoyable puzzle. Yes one clue about Yorkshire dialect - other clue is about bright spot - but that answer starts with a different letter.
If that's the 10 letter answer beginning with 'p...' ('Bright patch with refined laser...') it starts in an unchecked cell and isn't entered conventionally.
Is it possible you've got 'bara' (brith?) in place of the 'p...' word, Noble Roman? If so, you've gone astray with your breads somewhere along the line.