Pulling the laptop apart was uneventful without anything flying across the room or those fiddly small connectors - which I can barely see - snapping, removing and slapping in the new GPU was just six screws and a bit of thermal paste, and when it was all screwed back together, I didn’t even have any screws left over. Switching on and debian detected it happily, nvidia-smi and nvidia-detect were happy, and apt just installed the nvidia-driver without fuss.

Other than a loud snapping noise now made when the laptop is closed and hooks into the catch thing (perhaps it should always have been like this), it was quite dull and boring really.