Yaw've med my day yaw ave
They aren't doing away with diesels/petrol. If you buy a new one on the day before the ban comes in, it should last you the rest of your life.
I wonder how fast filling stations will disappear when the ban comes into force, I would avoid buying a new diesel as they will almost certainly be a bigger target for higher tax in one form or another.
Maybe fuel forecourts will set up charging points in place of pumps or just disappear altogether as time goes on.