Update
After not using the car during our recent hot and humid spell, I took it out last week and the speedo had resumed full function.
So probably a dry joint?
All was well until I hit a pothole at 54kph and that is where the speedo needle stuck and the odometer disappeared.
Give me strength!
This may just be a coincidence... But...
A pothole caused my speedometer/odometer to stop working (2012 4/4). Turns out that part of the dash loom shares a fuse with the seatbelt 'tell-tale' wiring which runs alongside the seat runners to the seatbelt sockets. When the seat jolts on the runners (pothole) it slices the wiring and shorts...