They shored up the wall by applying pressure with 4 wide planks of wood.
Then, they drove 4x4's between these planks and posts buried in the ground across the driveway:
They carefully hammered the 4x4's down until they had moved the wall 3/4 of an inch and back in a relatively good position.
After moving the wall, the masons needed to secure it using Helifix ties:
This tie is 3/8 inch thick and 8 inches long.
First a pilot hole is driven; then, the tie is countersunk into the wall with a special driver. Here's what is visible from the outside:
A little patch of mortar and it should be hard to see where they are!