Classic...
The job is done, the Makita cordless drill worked fine, the 3'6" auger bit worked a treat, just had to back it out from time to time to clear the very tip (small screw-like threads on the pointy bit got a bit clogged in the wet wood) Bob did the drilling and he said it was fine. The drill comes with a nice long handle that really helps with the torque.
We put two 3/4" threaded rods in, one through the cracked section and one above through both leaders. We had put a Spanish tourniquet and a 4:1 system up high and hauled on it to bring the crack as close as possible.
Once the bolts were in and secure, I tightened the cables that I had put up last week, and let go the 4:1...nothing moved, tight as.
Pictures tomorrow.
Thanks for the input gents, it all helped!