WALOS
There is NO fuel duty on veg oil for private use for the first 2000ltrs
You really need a twin tank system and a changeover valve .
You stand a good chance of destroying your injection pump if you go above 30% SVO in the winter (esp this year )
Up to 90% clean SVO plus petrol is a good blend
up to 80% Clean SVO plus derv is also good
I used about 1500lt in my crap citroen zx td and saved more than i paid for the car
Making WVO into fuel is dangerous as you have to use meth oxide which is easily absorbed through the skin and causes long term cell damage
Your T4 engine will run unmodded on a blend , better in the summer /
You will have to change the fuel filters once , or more likely twice as the veg oil pulls all the gunk from the system and deposits it in your fuel filter ( cue lots of misfires and smoke)
SVO is more like £1.10 a ltr , 70p is filtered wvo which usually needs further treatment