Elements of four symmetrically disposed unclued lights confirm the 5 Down. Enumerations indicate lengths of clues’ ‘full’ solutions.

Across

1 People are pruning every European tree (6)

6 Cook cut gooey rock cake (7)

11 Bishop leaving foundation unaltered (4, two words)

12 Skywriting? (9, two words)

14 Radical Left holds back boy (5)

15 Distort lower grades by class (6)

16 One very leggy girl weed picked up (9)

19 Obtain unlimited happiness (6)

21 Senseless how love ends (5)

22 Baby’s back, bound for Glasgow (4)

24 Harbours shelled on a key date (6)

25...