For the record...
I was extensively involved in an SA flight school and our solo rules were directly guided by our part 141, and what was approved by the CAA, which said it's up to an instructor to decide but not before 12 hours (i think it was 12...).
Having said that the legend who trained me heaved me out of the nest at 7.2 hours...
Also i know of one student, saw the paperwork myself, who was signed out solo (all initial helicopter skills competent) after 3.1 hours. Granted, he is also the highest private pilot fast-jet flyer in the world (1000+ in ex-military jets) so it was no huge surprise.
That's my bit.
HP.