A US research study, by Carvalho et al, determined that using neuraxial anesthesia during External Cephalic Version (ECV) increases the rate of success from 38% to approximately 60%. By making the uterus more lax and flexible the doctor is able to manipulate the baby's position with more ease.
Some gentle and skilled doctors I know self-report a 50% success rate without anesthesia.
One thought I have is that by softening the ligaments around the womb anesthesia may not be necessary.
I suggest the Flip a Breech activities described on the Spinning Babies Website to help make the womb more balanced and flexible. With increased body balancing, the baby may flip his or herself, or make a manual external cephalic version more likely to work. It would make a nice comparison study.