The fuel 7 Eleven use (I believe) is Mobil. Meaning their premium would be the old Synergy 98 that Mobil used to sell.
Decent fuel and I found my car always ran nicely (and got better mileage) out of it than VPower or BP Ultimate, or Caltex Vortex.
Vortex and Synergy 98 the car gets best mileage and runs nicest on. BP Ultimate I get far less mileage than other 98 fuels. VPower is normally too friggin expensive and doesn't really give me more mileage than Synergy.
Plus the local servo is a 7 Eleven and cheapest around.