Ahhh now that makes sense! 801 IS the PR!Yes the eligibility date for the 801 is for PR, (as the 801 is the Permanent visa) it's when you're eligible to apply not when it will be granted.
Yours is March 2017 by the sounds of it, so yes, you can start the application process in January 2017 if you wish, although given the wait times at the moment applying early seems to make no difference. They wont look at it until March or later anyway.
Once that's done and PR done I can go straight for citizenship too I believe as I'll have been here for 4 years, seems daunting!
Thanks guys for answering, this forum is amazing