From writer's docs:
Ann - 21
Arthur - 19 (so I think DEFINITELY the laugh lines needs to be removed!!)
Christina - 21
Neville - 26
Svetlana - 22
Roger Steel - 30
Mei Ling - won't say/doesn't know - but between 18 and 24 probably; looks young but tough beyond her years
Hamilton - 28 - but looks older, more weathered than RS!
Anja - 18 (twin of Abhay - facially identical)
Abhay - 18 (twin of Anja - facially identical)
So I actually don't know where I read that the characters "must look older". Maybe was just in my mind
Only Roger Steel is 30!