Glad things are progressing Viv. I would wait a bit longer before I left them together while I was gone. It took several months before I left Maddie and her sis together completely free and unsupervised (and this was just while I was in and out of the house) Now, a year and a half later, I don't worry about them being together alone.
I gave myself
plenty time to see how they interacted with eachother
Good luck!