There are one or two of us in darkest West Wales with experience of running a diesel car on veg oil.
Dan, the main culprit is promoting the idea at various exhibitions and shows during the summer holiday season. He did a Lands End / John o Groats run last year to prove the viability. His prefered fuel is 5 litre bottles of the stuff from Tescos, and although he is honest and pays the customs duty, it would appear to be cheaper than pump diesel. Don't know how the long term life of the engines will be affected, but no problems at the moment with cars being used every day.
See
www.vegoilmotoring.com Mike Godsell