I've always used 95 RON 10% ethanol blend from United. It costs 4c / L less than 91 RON non ethanol unleaded and mine has NEVER pinged on that stuff.
If you have a United servo nearby give it a go.
The last 2 fills however I've used their 98 E10 and of course no pinging at all but I reckon I get another 50Km per tank which makes it almost economical enuf to use every day.
The only time I used normal 91 RON didn't go so well. Pinged when WOT @ low revs and it knocked the edge off perfomance and I only got 500 Km per tank.
We also have a Renault Scenic II and it MUST run on 95 RON minimum or fault codes come up on the
ECU.
I guess any Euro tuned car should be using 95 or higher.