Did you have a speed limiter engaged? This is a dangerous piece of kit as it is prone to picking up speed limits on adjacent roads and bridges and "adjusts" you speed accordingly. It happened to me doing 70 mph on a dual carriageway. On going under a bridge which carried a road with a 30 mph limit the car autonomously braked extremely sharply. It was fortunate there was nobody behind me.
The EU is going to make this mandatory on new cars I understand. Whether or not we remain in EU the UK will have to comply or risk being unable to sell cars to Europe.
