Bird gang affiliate
I'm 99.9999999999999999999999999% sure it's 12 months from when you pay. My renewal date is in April.
For those who are already premium members...If you click on your username, then onto account upgrades - it will tell you in there, when it expires.
I thought and hoped that might be the case, thanks @globaleagle
Edit: I’ve just updated to premium, guess I’ll know for sure in a couple of days whether I just signed on for ‘2019’ or 12 months!