Here is the full list of all 49 Battle Of Britain achievements.
V2 Hunter 10X
V2 Hunter 50X
V2 Hunter 100X
V2 Hunter 500X
V2 Hunter 1000X
Me 262 10X
Me 262 50X
Me 262 100X
Me 262 500X
Me 262 1000X
Me 109 10X
Me 109 50X
Me 109 100X
Me 109 500X
Me 109 1000X
Bullet Collector 100X
Bullet Collector 500X
Bullet Collector 1000X
Bullet Collector 10000X
Weapons Expert 10X
Weapons Expert 50X
Weapons Expert 100X
Weapons Expert 500X
Weapons Expert 1000X
Lively 10X
Lively 50X
Lively 100X
Lively 500X
Lively 1000X
Spitfire Expert 100X
Spitfire Expert 500X
Spitfire Expert 1000X
Spitfire Expert 5000X
Spitfire Expert 10000X
Mosquito Expert 100X
Mosquito Expert 500X
Mosquito Expert 1000X
Mosquito Expert 5000X
Mosquito Expert 10000X
Meteor Expert 100X
Meteor Expert 500X
Meteor Expert 1000X
Meteor Expert 5000X
Meteor Expert 10000X
Bomb 10X
Bomb 50X
Bomb 100X
Bomb 500X
Bomb 1000X