Cryptic crossword - The Scotsman 25/09/14

ACROSS

7 Besiege hill taken by sergeant-major (5)

8 Spare seat designed from branches (9)

10 Continue to have some control over graduate (6)

11 Change a long note in front of 13 across (8)

12 Rough long walk over new terrain, initially (8)

13 Call up band to embrace syndicate (4)

15 Races about in some occupations (7)

17 Was instructed, provided one split two little boys (7)

20 Power everything with stuff (4)

22 Island in the far north can be quite insecure (8)

25 Have to deal with hole in the import-export balance (5,3)

26 Listen to record, taking in one chord, initially (6)

27 Rave about edits needed for broadcast (9)

28 Head off insecurity, with some exasperation (5)

DOWN

1 On the way, about to run into a tram (6-3)

2 Arrange a musical instrument; one’s made to close (8)

3 Nitpickers would like to see a little boy in short trousers (7)

4 Hesitated to use force, having changed (8)

5 High point, getting a couple of runs, is a bit unproductive (6)

6 Do some workers have a second income? (5)

9 Wanted part of a bet at the poker table (4)

14 Contemplated being freed up, etc, on line (9)

16 Connect with, for example, but is put down (8)

18 Use additive in dieting, but also in wining and dining (8)

19 Get wrong assignment in a remote settlement (7)

21 Was a boy attracted to a new start? (6)

23 Initially, say any number expected are all there (4)

24 May have to deal with some extra demands in 25 across (5)