It's a sad fact that after a bit of a land-grab for US shows coming over the UK a couple of years back, when you could pretty much be assured of seeing everything, we've started to "lose" shows recently, presumably as they just don't pay their way. It's a bit of a vicious circle, of course, as if you wait 6 months to screen a show that would have a small, yet devoted audience, they'll have aquired it by other means by then, reducing it's audience further. Worse, some channels have bought shows and then handled them badly, burying them late at night before dropping, as fans of Orphan Black, Person of Interest, Once Upon a Time, and Justified have all found to their cost. The metrics for streaming services are different, of course, and so Netflix, Amazon and even Sky have picked up these shows to stick behind their paywalls, in a bid to make those paywalls more attractive. And so it is that iZombie finally reaches the UK, courtesy of Netflix.
