Huawei Y6 II Compact.
Price is only available to those with a Vodafone or O2 SIM that is eligible for an upgrade. The handset will be unlocked to all networks.
This looks like a reasonable spec for the price:
5" IPS 720p Screen
1.5Ghz MT6735 SOC
16GB Internal Storage
13MP Main Camera with Dual LED Flash
5MP FFC with LED Flash
Android 5.1 with EMUI
Full specs and a detailed review of the handset can be found here: http://www.notebookcheck.net/Huawei-Y6-II-Compact-Smartphone-Review.174558.0.html
According to cpw info it has Android 6.0 marshmallow