Here, Caroline has nicked a rather nice outfit off of Yuko Ichihara from 'xxxholic', while Alex is the tenth Doctor from Doctor Who. A Time Lord and a space-time witch - you've got to wonder how that meeting would play out ... though, going by their personalities, I don't think it too unlikely that they'd just end up talking about food.

And, yes, the reference is pretty damn obscure, but I can't help it - every time I see cakes with those little silver balls on, I hear David Tennant saying 'Edible ball bearings! Genius!'.

Claudia is DCI Gene Hunt and Sam is DI Sam Tyler, both from 'Life on Mars' of course. Apologies to any one who is now haunted by images of Philip Glenister with bunches.

And last but not least, the Captain as Lord Peter Wimsey and Harry as Bunter, from the mystery novels by Dorothy L. Sayers.
I realised after drawing this that Bunter was also a Sergeant - admittedly in the army rather than the police - so it's actually quite appropriate. I doubt that would make Harry feel any better though. I can't imagine him being happy picking out the Captain's socks in the morning, even if he did still get to help solve murders and rescue people from bogs and stuff.