Kieran Bew has played two different characters over the course of the series:
- Episode 14.6 First Casualty: Part 2 (2011) - Lt Stephen Lockford
- Episode 14.5 First Casualty: Part 1 (2011) - Lt Stephen Lockford
- Episode 8.8 Body 21: Part 2 (2004) - Stephen Wiltshire
- Episode 8.7 Body 21: Part 1 (2004) - Stephen Wiltshire
Shaun Parkes has played two different characters over the course of the series:
- Episode 19.6 Life Licence: Part 2 (2016) - Bennett Walker
- Episode 19.5 Life Licence: Part 1 (2016) - Bennett Walker
- Episode 8.8 Body 21: Part 2 (2004) - DI Freeman
- Episode 8.7 Body 21: Part 1 (2004) - DI Freeman