In six answers the wordplay ignores an item. These items (two of them identical) are not listed as specific 27 of 22 in Chambers, unlike the other unclued entries.
 

Across

 
1    Extra thin pins cleaned up with this? (5)
6    One that’ll teach you a measure of warmth (8)
12    Hopes dashed with 31 restaurants (10, hyphened)
13    Horse runs into different one (9)
14    Allan Wells, perhaps, absent from racetrack? (4)
15    Censor adjusted EastEnders, essentially as seen on TV (8, hyphened)
16    Stick holds sack, calculating its volume? (6)
17    Problem when 22 for a group’s composition (5)
21   ...