In NL I use any 95 RON, generally the cheapest
Supermarkets dont have petrol stations out here, maybe Makro but thats about it.

I used to use shell all the time as 2 of them were right on my way to work, but it seem all my local shell garages have turned into JETs so i now go there if I'm low but normally hunt around for a BP

One of the shell garages in Aberdeen also changed to Torq, I have never heard of them. Although still at least 5 shell stations near me still lol

I've been using Tesco's normal unleaded for 2-3years and then once a quarter i will fill up with their super unleaded to clean the enginer a bit...seems to have worked fine and never had any problems with idling etc.

my magnecor leads & 60mm throttle body made a massive difference to the engine in my opinion, although not to power figures, just general running of the vehicle! all been stripped now though, bad times :/