I have a 2019 Fiesta and since using e10 petrol my petrol consumption has gone down and have used a quarter of a tank and only done 63 miles since filling up. I'm not the only one as my nephew has noticed the same in his car. 

Ah, well that's good then. If your consumption is down you're getting more to the gallon. Most have found it's gone up.

Me and my partner were having a good rant about this, I honestly think Im getting less MPG than what I normally do.
 

I have got a Focus St Line-X 1.5 182ps, which already drinks the juice if you put your foot down, I normally put £40 a week in the tank which gets me around 3 quaters of a tank from near empty depending on the price, normally use Costco which is 1.25p a litre. Usually lasts me a full week or a day over, but I’m finding myself filling up every 5 days now. My partner is the same with her Volkswagon T Roc 1.5. She fills her tank completely and normally gets two weeks out of it, but now she is filling up after 10 days.

I honestly think this E10 is burning alot faster than E5, I have also just ordered the Focus ST 2.3 petrol this week so I will be building a second home at my local Petrol station at this rate.

1 hour ago, AP1878 said:

I honestly think Im getting less MPG than what I normally do.

Tbh, it's not the most accurate comparison method when fuel prices are generally on the rise anyway.

Both your cars have trip computers - have you noticed a big change in your average mpg readings?

Better still, have you tried calculating mpg accurately by the "brim to brim" method?

As mentioned on other threads, I've not yet noticed any change from my normal mpg after several tanks of E10.