I've always used supermarkets fuels in on all my cars in the past. I have had a mechanic tell me that a few times he has found engines with algae growth in the head due to the owners always using supermarket fuel.... Not sure if true or not, again seen no real evidence myself.
However, since buying my XC70 at the start of the year with 40,000 miles on it, (I am sure the previous owner would have been a supermarket fuel type user), I have been more inclined to use Shell of BP fuel stations for Diesel. Now the cost difference isn't really that much. Ie shell/BP is maybe 1 - 3p more per litre than say tesco. A full tank, maybe a couple of £s difference. I plan to keep this car a while to putting in a better grade of fuel, that I do know. I do put in redex or wilsons oil diesel treatment to keep things clean. Maybe once every couple of months I'll go for Shell V-Power.
At the end of the day it's a personal choice, but Volvo will have established what is the optimum fuel for their vehicles. If you do a lot of miles every week then it may not be cost effective. If a tank can last a couple of weeks with small shuttle runs, then maybe not so bad. For me I have moved away from supermarket fuels unless I need to use them, for the sake of engine longevity (so I think), but would be good to find an actual study on this.
Still there's speculation....
https://www.simplemotoring.co.uk/sup...branded-fuels/