For anyone that might be interested in this mobile OS.
At present it is limited to a very phones partly to aid development by having a more fixed hardware platform and as the Experia XA series phones are Sony products and Sony issues unlock codes on request. the more techy and adventerous can leverage the Linux base to make their own custom image which works with other hardware combinations, all you need is the ROM unlock.
It is very gesture and swipe based which feels odd for a few minutes until it clicks with you then it's rather simple. It is also very consistent in that the apps work in the same way.
Oh and it configured itself to use the Giffgaff service, including adding all of the service support numbers without any user input.
If you don't mind installing it yourself and want to be a bit different from the herds using IOS or Android then it does represent a viable phone platform.