H.L.
I think you may need to be a bit more specific as you will get three different sets of answers for sure. 'DHL' LEJ comprises three core companies:
EAT (BCS) D reg 757
DHL Air UK (DHK) G reg 757/767
Air Contactors (ABR) EI reg A300
Three completely different companies, on different AOCs, different terms and conditions and roster policies / allowable FDPs.
I am only a humble groundie, so I will leave it to my mates aloft to respond to your questions.
Good luck, hope they get back to you,
Bored