ive done it for years on a corina. 220,000 brother still driving it
Surely you must appreciate that a 2007 Avensis D4D T180 is completely different to an old Ford Cortina? Modern diesel engines are both highly complicated and very sensitive peices of preceision engineering. They are not the hardy diesel engines of old.
You have ultra high pressure injection systems which can be wrecked by using the wrong fuel.
Why do you insist on doing stupid things to this car?