Andrew, try a search for "biodiesel"
HERE. There are some 3-4 threads worth to read.
You can also ask this question in forums other than LR, mainly the ones about the vehicles that use the same TDV6 engine,
the list is here.
I can't help you more since I don't have a D3 TDV6. What I know is that the owner manual says not to use biodiesel more then 5% and that LR voids the warranty if you do.
Some food for thought would be reading about vehicle manufacturer's efforts in trying to develop modern day diesel engines to be biodiesel compatible. One example that I remeber of:
Renault launches B30 Biodiesel vans (see also renault trucks). Just google for more info, plenty to read.
Mind that they are struggling for a BD30 or BD50, not BD100.
So, feeding BD to this modern diesel engines, with a very high injection pressure, ceramic multi nozzle injectors and so on is not quite a simple thingy.
What's funny is that, after reading the topic title, I read in a hurry your message like this: "Hello, I'm thinking about
ruining my Discovery on biodiesel ..... ", he,he.