6 shared reasons: studio: BBC Studios Documentary Unit studio: BBC Studios Documentary Unit studio: BBC Studios Documentary Unit studio: BBC Studios Documentary Unit studio: BBC Studios Documentary Unit studio: BBC Studios Documentary Unit

5 shared reasons: studio: BBC Studios Documentary Unit studio: BBC Studios Documentary Unit studio: BBC Studios Documentary Unit studio: BBC Studios Documentary Unit studio: BBC Studios Documentary Unit

4 shared reasons: studio: BBC Studios Specialist Factual Productions studio: BBC Studios Specialist Factual Productions studio: BBC Studios Specialist Factual Productions studio: BBC Studios Specialist Factual Productions

3 shared reasons: studio: BBC Studios Documentary Unit studio: BBC Studios Documentary Unit studio: BBC Studios Documentary Unit

3 shared reasons: studio: BBC Studios Specialist Factual Productions studio: BBC Studios Specialist Factual Productions studio: BBC Studios Specialist Factual Productions