I stopped at the end point and left long threads, which I later went back and threaded them into a needle with which I then took a long stitch between the layers, pulled it taut and snipped off close to the fabric, this leaves the long ends inside the quilt. I have bought a packet of 'easy threading needles' ready for when I get to this stage of my next quilt, as all the threading up for one stitch gets tedious, but it holds just fine. You can pull the under side thread up and finish off both ends at once, or work from the back, play and see.
Rosemary