Really stuck.
1a. A large bear backing fair game (4-2)
- o - - - a
3d. Initially police called after minor accident (5) - - a - g the first letter of this one is the fourth letter of 1a.
11a. Joined one round point (4) i - e -
15d. AThey take charge temporarily, regarding men's toilet (7) r - g - - - s
21a. Duck in park finally makes another animal sound (4)o - - -
All help is greatly appreciated.