Annie, 14D is one of the clues with a longer answer than the grid cells, so you can reasonably expect that there's a clash cell somewhere. All the clashes bar one are in the first or last cells of answers. So the clash cell is the first cell of 14D. Go for exactly what the wordplay says : a common word for 'grain' with a common word for 'one particular' inside. By the way, the contents of all the clash cells, prior to replacing by dots, contain words.