Yes I remember the 2,3,and 4 star. 5 star wasn't available when I started driving but my old Datsun 100A used to run on 3 star or when I was skint 2 star [Linked Image].
3 star was just a blend at the pump of 2 and 4 star. More than once I've filled up with 3* and noticed the car going better than normal. Turns out the garage ran out of 2* without noticing. Can't remember it happening the other way round [Linked Image].

When the Formula Shell was available the old Datsun went like it was on steroids. Pity Vauxhall (part of GM) used dodgy valves and seats in some of their Astras and blamed the fuel, spoiling it for the rest of us.

The only reason I remember the diesel being far cheaper was that my parents ran their own business for years and I used to fill up the vans.