I had a Fiat Doblo for 7 years. Each time I put standard French diesel in on the first French fill the engine would go into limp mode after a few hours of running on this French diesel. Topped up and filled up subsequently with Shell V Power and voila, within the first hour or so the engine would come out of limp mode and start running normally. This happened on three separate occasions. On the 4th French and subsequent French visits I only ever premium diesel.
I was told French standard diesel contains a higher proportion of biomass diesel when compared to U.K. diesel. French premium diesel contains hardly any if no biomass. Now this may be right or wrong but my suspicion is there is something afoot here to keep emissions down. Premium diesel may well be less environmentally friendly but I never have limp mode issues with it.
When motorhoming in Spain I use premium diesel 100% of the time, normally Repsol, as price premium in Spain is tiny and diesel is cheap anyway.
When in France probably every 4th tank with premium. We have a Fiat based MH and yet to have a limp mode issue so maybe what I described above was a Fiat Doblo thing.
It may be psychological but I do sense I get marginally more MPG when in cruise control on the motorways when using premium. Have to monitor the trip computer more closely in future!