The duo was supposed to be put up for grabs in the U.K. starting a few days ago (April 1, to be more exact,) but for some reason the releases have been pushed back. On the bright side, both devices are still due for April launches, with the 720 expected in stock as soon as the 8th.
Clove is your go-to retailer if you have your eyes set on the SIM-free Lumia 720 (available there for £299.99), while if you prefer the on-contract version, you can get that one for free with select O2 or Three Plans.
As for the 520, this is going to be a little late, with both Clove and Amazon listing shipping to start on April 22. The Pay as you go price point is £169.99 with the former and a heftier £198.79 with the latter. Needless to say the 720 is the more attractive fellow here, what with its 4.3-inch display, 6.7 MP snapper and all, but the 4-inch 520 is a nice budget choice too, coming with a 5 MP camera and a dual-core processor in tow.
<Source: Unwired View>