Used and abused

We had a long trip to do across the Alps today.
I convinced B that it’d be fifty quid cheaper but take a bit longer to go via the Col du Mount Cenis rather than the Mont Blanc tunnel. And tbf I was rather looking forward to that. (But we ended up going through the tunnel because I’m a twat).
So I topped the tank up and we headed off.
Shortly after leaving the garage, I thought the engine felt a little rough. I looked down and saw the engine check light was on.
My first thought was oh no I put diesel in. But I thought no I can’t be that stupid, it must be ignition related.
So stopped at the first services and looked under bonnet but knew it’d be a fool’s errand in 35 degrees and full sun (Italian service stations are CRAP)
So we carried on and B said, “Could you have put diesel in it?”
And that was when I decided it was indeed possible that I had - just under half a tank full.
I can confirm that a naturally aspirated Suzuki Swift Sport will still run on a 45% diesel petrol mix.
I drove for another 140miles - I’d say the car did better mpg than with plain old petrol. Then topped up the tank - and discovered 30% diesel mix is a vast performance improvement but still like comparing a Renault 4 with a 2CV.
Edit:
What utter claptrap. I must’ve been 45% wine. There’s no way any petrol car would run on 45% diesel.
I put petrol in the tank. No receipt so no proof - but it was petrol.
Common sense says it’s a leak in the induction that’s confusing the MAF sensor - it’s just a coincidence that the fault appeared within a minute of leaving the petrol station.
Will check soon.