The unclued lights (one of two words and one hyphened) are of a kind, all verifiable in Chambers.
 

Across

4    Night-flier in gear (11, two words)
11    Fancy pictures from one publication with topless sequences (9)
14    City faraway from Helsinki, evidently (4)
15    Aunt Sally is retiring (3)
18    Dropping openers, new eleven win cheer (7)
19    Morning porridge for old bishop (7)…
22    …gay bishop, flexible (6)
23    Altered course on board being transported (6)
27    Welsh lake engulfing small wood (5)
29    Second Roman soldier beams (6)
31    Joints giving trouble in the feet, not the head (6)
34    New oboe pit in ecological community (7)
35    Dressed in a suit for...