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Thanks AlexP... the problem is this does keep happening, I just can't make it happen on demand! The fact it happened both ways in the channel tunnel suggests something is either loose/broken or shorting out under certain conditions. I was 30 years in the motor trade (before I saw sense) and I'm well aware of the "peculiarities" of French cars but this is safety related and shouldn't be chargeable.

I'll be contacting Renault direct later... wish me luck!!

I think you can contact Renault officially. Tell them the problem and send the photos/videos if you have. They must check your car on warranty. 
You can use my photo if the errors and lights looked the same. I suggest mounting a dash cam that can see the dashboard if you have one, in case things happen again until you get your car checked. 

have you considered another dealer? could be more accommodating