As I have posted before, I always use Premium grade in my 1.4. Not being concerned with performance, any possible improvements there are not noticed; but what I do get is about 10% better consumption (so more miles in the tank) at a cost of about 10% more, and so the costs and benefits just about equal out. Also I will avoid E10, as if the motor is left standing for prolonged periods, which has happened to many of us recently through lockdown, the Alcohol in the E10 absorbs water from the atmosphere and is known to occasionally cause some corrosion. It has also been reported to 'dry out' rubber hoses (from autotechnician.co.uk).
Thuis I am with Gremlin, move to the higher Octane rating fuel and use premium grade fuel.