The unclued lights (two individually, both of two words, one an abbreviation, and five pairs) are of a kind. One further theme word appearing every third week should be highlighted.
 

Across

1           Men Prescott battered in dispute (11)
7           Liquid — mostly light red (3)
11         Beat about the ears? (6)
15         One in a suit showing spirit (5)
16         Question and answer about Long Island’s decline (5)
17         Active Liberal in breeding establishment backed the big folk! (6)
18         Local strains from most of Polish region (5)
20         Extremely succulent food for small carnivores (6)
22         Make a meal of a symphony! (7)
27         Colours blended in Dresden (7)
29         Great weight of...