I came home from my trip to see that our tree had been rodded and cabled. There's 2 rods. See the other one up in the crook of the tree? The wound is healing nicely and hopefully these rods and the associated cables will keep this big thing up for many years to come!
The guys tell me that as the tree grows - which will take years - the tree bark will sort of 'knuckle' over those washers/bolts/end of the rods, so they might disappear somewhat?