Hi all... for those that are desperate to have Cyan on Nokia 1520, I live in New Zealand and have a Hong Kong CV firmware, I successfully down graded from DP 8.1 to 8.0 using Finland Firmware though Nokia care suite. As soon as I booted back up after downgraded the phone started updating to Official Finland Cyan 8.1 on firmware # 02061.00066.14253.4003 hardware # 5.0.0.1
noticeable difference is the little arrow on the data and WiFi signal, now has a USB option in settings and my wireless charger now completes to 100% quicker than it used to on D.P 8.1.
The fact that the 1520 was never released in NZ it makes no difference to me who the original firmware originates from... once you get passed the Finnish language and the phone reboots you then just delete the software the bloatware that comes with the regional rom and every thing works perfectly... I have set the region and language to USA and have Cortana working seamlessly as well, with the exception that the NZ accent is a bit harsh for Corona I would say it is a out 90% accurate.
So rather extreme way to go, but if you are going to have a hernia because you are being made to wait then just grow some brass ones and do what I did and enjoy.... now I will get on with life and twiddle my fingers until the next big thing/ update comes along.