In my view the best way to change a club is be in it, if you're outside you have no influence and nor should you.
From what I can see we appear to have negotiated an exit from the club with the lack of influence that entails but have agreed to continue to pay membership and abide by some of the rules very bizarre. This is certainly a worse position than where we were so the response is to reject that option storm off in a huff and leave with the door slamming behind us without any plans as to what we will do now. This once again leaves us in a worse position than before (even if it is for a short period of time).
A second referendum won't help, if the result stays the same we are still out without a plan, if it changes we have to go back to the other members of the club, say we're sorry and we won't do it again which again is a worse position than where we were.
Ultimately we have screwed up, at the start of this process I could see no demonstrable benefit from leaving and IMO we are going to be worse off regardless of what we do, one of many reasons why this remainer is seriously considering being a leaver.