I recently had fibre installed at my place, and would like to run a couple of CAT7 cables to rooms which don't have existing jackpoints. There is CAT6e in the walls to most rooms, but not to the office or master bedroom (but there is one in the pantry...). Everything is streaming in our place now, excluding gaming on the Steam Link that lives near the TV, where I would prefer to the kids to sit as they argue over the proper way to be a horrible goose in the village. 

The Chorus-branded box on the outside of our house, where the fibre comes out of the in-ground duct, goes through a short internal duct to a Hills HomeHub cabinet. In there is the ONT and a new network switch. The router sits upstairs, using the existing CAT6e network.

I would like to have at least one CAT7 cable go from the switch, back through that internal duct, out through the rubber-grommeted holes in the bottom of the Chorus box, and around the outside of the house (in a sheltered spot, alongside an external gas line) until it can go back under the house, where I have free reign and good access to the underside of the walls where I want new jackpoints put in. 

I think I can use the old copper line which is still in the duct to draw at least one line through, and I think there might be just enough room for an additional cable in the duct. The old copper appears to have been terminated in the Chorus box (each colour/white pair is enclosed in a plastic thing). The back (wall) plate of the chorus box seems to have had a hole drilled through it just slightly off-centre to the duct, which might need to be enlarged to get better access, or I might have to take the back plate off the wall temporarily. Or both.

Does anyone see any potential problems with this installation method? Is the fibre cable likely to be too fragile to have cables drawn along it? Does Chorus prohibit fiddling with the box?