Led to believe your Disco may also die in the forseable future if u mix it wrong!
All your doing is insuring the SVO ignites, but the fuel pipes are 4mm thick so it should be heated enough this time of year depending on your mixture, im 50D/50SVO at the moment but intend reducing it more in warmer weather. Read the topics related to this they helped me. Any saving on £115.9 per ltr is a boost!
adding the petrol helps ensure that the oil doesnt go gloopy when the temp drops it's got nothing to do with helping it ignite
i've been running near 100% even when it's been frosty in the mornings i've had no problems starting