Each of thirteen clues contains one misprinted letter in the definition part. Corrections of misprints spell a phrase involving a pair of items. Unclued Across lights are examples of one of these items, and unclued Down lights are examples of the other. Ignore an apostrophe in a clued light.
 

Across

 
1 Crease in leg left by special garter (8)
6 Hair’s restyled with new length (6)
11 Old-fashioned glance reflected trouble admitted by editor (5)
13 Chest well inlaid with silver line (7)
14 Palm in westward desert sheltering fowl (6)
17 Empress, for instance, fashionable (8)
21 Muse in retreat, not eager for material (8)
25 Spirit medium...