On the leaving thing, I think my point was that we will have left the EU, and be out of the institutions, etc.
However .... the transition agreement ensures that, day to day, nit much changes until that ends.
The problem is that the transition agreement isn't yet nailed down. It's currently working it's way through the Lords, so far without fanfare or much obstacle but it's now at exactly the point (3rd reading and report stages) where any spanners the Lords try to throw in the works will get thrown. Now, I'm no expert on parliamentary procedure but as I understand it, if it gets returned unamended, it goes straight fir Royal Assent, and .... job done. But if the Lords do amend it, then it goes back to the Commons who can, of course, unamend it and return it, and a potentially lengthy ping-pong starts, or we start down the Parliament Act route, which also takes time. Time that isn't there.
Given that the 31st Jan deadline is set by EU-UK agreement under art.50, it isn't affected by UK parliamentary antics. It's a defined, hard deadline. And if we haven't passed the Withdrawal Bill (the current '19-'20 one), AND the EU ratified it, we still leave on 31st, but .... no withdrawal bill, no transition period.
It's hard to see the date of us leaving legally changing, at this late stage.
Assuming we leave with a transition period, it still only lasts 11 months, unless both UK and EU agree a further delay, and we change UK law, and the PM accepts what wil. undoubtedly be huge political damage by going back on his oh-so-often repeated promise not to change it.
So by far the most likely timetable seems to be legally out in a few days, 'transition' ending with end of this year, whatever state an FTA is in, and us being right out by Jan 1st, next year.
Yes, it could change, but to me it looks unlikely, especially given some categoric statements that a choice between friction and alignment, the government have clearly and publicly nailed themselves in the direction of friction not alignment, or at least, not be locked into alignment.
All of which suggests completely out by Jan 1st, 2021. Not all that long. Not long at all.