Hana is seen both in the current day and in flashback/photographs from sixteen years ago. However, she hasn't aged at all between the two time periods.
Superintendent Pullman suggests that the team examine the council's CCTV records from sixteen years ago to check a suspect's alibi. However, Home Office guidelines are that CCTV footage is retained for only 31 days (unless known to be needed in a police inquiry), and councils don't keep any footage for more than two years. No CCTV recordings would be kept for 16 years, and Pullman would certainly have known this.