1: Bill board reflected family meal extra (5,6)
2: Exchange concealed proprietary knowledge (5,6)
3: Repack? Foe repacks, but gives nothing away. (9)
4: Trailer crashed in second test (7)
6: Headstrong stag takes over the marsh grass (5)
7: You audibly ram partner (3)
8: Bend in the middle and wind back (3)
14: 27-across about starting off 1-down world unconditionally (2,3,2,4)
15: Left with pal carrying new gold case (11)
19: Crushed bones, say, as source of sauce (4,5)
21: Dirt caught in footwear (7)
22: Hungarian composer on CD extra, perhaps, with Norwegian composer (7)
25: Throw mud at information (5)
28: Later round without an opponent (3)
29: Choose to take the top off (3)