Ok then folks, I've looked a little deeper into the veggie oil thing and here it is.
There is a way for the common person to use veggie oil in the tank and get away with it quite legally. What you have to do is fill in a form for the customs and excise and register yourself as a private trader, the form is called ex103, the details are from this website
http://www.smartveg.com/legal.html
Once you have done this they will pay you a visit and look into the way you are producing your fuel whether it be from straight veggie oil or used, they will also want to know that you are keeping records etc, you then send off a declaration every month telling them how much you have made/used and what you will be paying to them @27.1 ppl.
Unfortunately there is a downside to all of this, it turns out from the figures I came across on another website that this country would have to produce 4 times more than what it can to meet the current demand as a direct replacement for diesel, for the small time person though there should be enough to go around.