In the pilot episode (Pilot: Part 1 (2000) & Pilot: Part 2 (2000)) Boyd (Trevor Eve) had a wife and baby. However by S1 (Burn Out: Part 1 (2001) & Burn Out: Part 2 (2001)) he is very much single and instead has an older son, who is missing.
In the final act, Boyd (Trevor Eve) had time to return to the office, get Frankie (Holly Aird) to analyze the blood sample, and contemplate his naval but still with this head start he and the crew arrived at the alley shortly after Marina.
Mel (Claire Goose)'s name was originally just Mel in the Pilot episode (Pilot: Part 1 (2000) & Pilot: Part 2 (2000)). However by Series 1 (Burn Out: Part 1 (2001) & Burn Out: Part 2 (2001)) it had been extended to Amelia.