If I can help you, I think this is a variation of the normal route of the Mount Blanc du Tacul, North Face. Not an hard route, but very dangerous for crevasses and seracs!
That rock in the lower part of the photo is the summit of the Triangle du Tacul!

Spot on

Thanks for that me being lazy and not checking out. We had gone up the tourist route ie cable car. Fantastic day that said.